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Kwon H, Li B, Xu M, Wang Q, Maqbool T, Lu H, Winkler M, Jiang D. Minimizing byproduct formation in bioelectrochemical denitrification with anammox bacteria. JOURNAL OF HAZARDOUS MATERIALS 2025; 492:138110. [PMID: 40187264 DOI: 10.1016/j.jhazmat.2025.138110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2025] [Revised: 03/26/2025] [Accepted: 03/30/2025] [Indexed: 04/07/2025]
Abstract
Autotrophic bioelectrochemical denitrification (BED) holds promise for nitrate remediation. However, the accumulation of byproducts such as NO2-, N2O, and NH4+, poses a significant challenge to effluent quality and climate adaptation. This study hypothesized that introducing anaerobic ammonium oxidation bacteria (anammox) to BED could alleviate this issue through synergy: a) anammox can utilize NH4+ and NO2- from BED without producing N2O, as seen in canonical denitrification, and b) BED can recycle NO3- from the anammox anabolic pathway. Results showed that Anammox_BED reduced NO2- accumulation by two-thirds, lowered the relative abundance of N2O by 80 %, and eliminated NO. Metagenomic analysis revealed that the anammox species Ca. Brocadia sapporoensis tripled in abundance in the bulk sludge. Meanwhile, Pseudomonas stutzeri and Bosea robiniae, species capable of reducing nitrate via extracellular electron transfer (EET) and supplying NO2- to anammox, halved in relative abundance, while the abundance of Stenotrophomonas acidaminiphila, a non-EET, ammonia assimilation species, doubled following anammox introduction. Metatranscriptomic analysis found upregulation of denitrification-related functional genes in Anammox_BED biofilm and survival- and motility- related genes in bulk sludge, possibly due to insufficient substrate. Overall, BED-Anammox successfully diverted the rate-limiting EET nitrite reduction towards anammox-driven nitrite utilization thereby mitigating the generation of unwanted intermediates.
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Affiliation(s)
- Hyejeong Kwon
- Civil, Construction, and Environmental Engineering, The University of Alabama, Tuscaloosa, AL, USA
| | - Bo Li
- Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Min Xu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Qingshi Wang
- Civil, Construction, and Environmental Engineering, The University of Alabama, Tuscaloosa, AL, USA
| | - Tahir Maqbool
- Civil, Construction, and Environmental Engineering, The University of Alabama, Tuscaloosa, AL, USA
| | - Huijie Lu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Mari Winkler
- Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Daqian Jiang
- Civil, Construction, and Environmental Engineering, The University of Alabama, Tuscaloosa, AL, USA.
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George MA, McGiffin D, Peleg AY, Elnathan R, Kaye DM, Qu Y, Voelcker NH. Nanowire arrays with programmable geometries as a highly effective anti-biofilm surface. Biofilm 2025; 9:100275. [PMID: 40230726 PMCID: PMC11994934 DOI: 10.1016/j.bioflm.2025.100275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2024] [Revised: 03/12/2025] [Accepted: 03/24/2025] [Indexed: 04/16/2025] Open
Abstract
Biofilm-related microbial infections are the Achilles' heel of many implantable medical devices. Surface patterning with nanostructures in the form of vertically aligned silicon (Si) nanowires (VA-SiNWs) holds promise to prevent these often "incurable" infections. In this study, we fabricated arrays of highly ordered SiNWs varying in three geometric parameters, including height, pitch size, and tip diameter (sharpness). Anti-infective efficacies of fabricated SiNW arrays were assessed against representative laboratory reference bacterial strains, Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922, using a modified microwell biofilm assay representing microorganism-implant interactions at a liquid-solid interface. To further understand the role of individual geometric parameters to the SiNW-induced bacterial killing, SiNW arrays with stepwise changes in individual geometric parameters were compared. The force that NWs applied on bacterial cells was mathematically calculated. Our results suggested that NWs with specific geometries were able to kill adherent bacterial cells and prevent further biofilm formation on biomaterial surfaces. Tip diameter and pitch size appeared to be key factors of nanowires predetermining their anti-infectiveness. Mechanistic investigation found that tip diameter and pitch size co-determined the pressure that NWs put on the cell envelope. The most effective anti-infective NWs fabricated in our study (50 nm in tip diameter and 400 nm in pitch size for S. aureus and 50 nm in tip diameter and 800 nm in pitch size for E. coli) put pressures of approximately 2.79 Pa and 8.86 Pa to the cell envelop of S. aureus and E. coli, respectively, and induced cell lyses. In addition, these NWs retained their activities against clinical isolates of S. aureus and E. coli from patients with confirmed device-related infections and showed little toxicity against human fibroblast cells and red blood cells.
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Affiliation(s)
- Marina A. George
- Melbourne Centre for Nanofabrication, Victorian Node of the Australian National Fabrication Facility, Clayton, 3168, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, 3168, Australia
- Department of Photochemistry and Photobiology, National Institute of Laser Enhanced Sciences, Cairo University, Giza, 12613, Egypt
| | - David McGiffin
- Department of Cardiothoracic Surgery, The Alfred and Monash University, Melbourne, 3004, Australia
| | - Anton Y. Peleg
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, 3800, Australia
- Department of Infectious Diseases, The Alfred Hospital and School of Translational Medicine, Monash University, Melbourne, 3004, Australia
| | - Roey Elnathan
- Melbourne Centre for Nanofabrication, Victorian Node of the Australian National Fabrication Facility, Clayton, 3168, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, 3168, Australia
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Australia
- School of Medicine, Faculty of Health, Deakin University, Waurn Ponds, 3216, Australia
| | - David M. Kaye
- Department of Cardiology, The Alfred Hospital and Monash Alfred Baker Centre for Cardiovascular Research, Monash University, Melbourne, 3004, Australia
| | - Yue Qu
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, 3800, Australia
- Department of Infectious Diseases, The Alfred Hospital and School of Translational Medicine, Monash University, Melbourne, 3004, Australia
| | - Nicolas H. Voelcker
- Melbourne Centre for Nanofabrication, Victorian Node of the Australian National Fabrication Facility, Clayton, 3168, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, 3168, Australia
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Australia
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Sharma N, Baruah DJ, Duarah R, Yadav A, Bora D, Saikia R, Jarugala J, Das MR. Smart-Sandwich: A Thin Flexible Sensing Device Based on an Agarose-Chitosan-Agarose (ACA) Triple-Layer Biofilm for Onsite Monitoring of Escherichia coli. ACS Sens 2025. [PMID: 40331915 DOI: 10.1021/acssensors.5c00038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2025]
Abstract
Portable, cost-effective, and durable thin-film sensors are essential for real-time E. coli detection, ensuring safe drinking water and public health protection. In this work, we developed a solid-state, flexible sensing device using an agarose-chitosan-agarose (ACA) sandwich biofilm for the selective colorimetric detection of E. coli in water. The chitosan in ACA biofilm functions as an artificial enzyme, exhibiting peroxidase-like activity, which catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). Upon incubating the ACA biofilm with E. coli, the agarose layers undergo enzymatic degradation by the β-galactosidase enzyme produced by E. coli. The degradation takes place due to the cleavage of β-1,4-glycosidic bonds. This exposes the underlying chitosan layer which enhances the catalytic activity, triggering a visible color change due to TMB oxidation within 30 min. The device achieves a highly sensitive detection limit of 6.8 CFU/mL, with excellent accuracy in real samples, further supported by android-based, smartphone-assisted detection. The developed solid-state, flexible ACA biofilm offers a novel, rapid, and reliable solution for onsite E. coli detection, combining sensitivity, stability, and ease of use.
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Affiliation(s)
- Nidhi Sharma
- Materials Sciences Group, Coal, Energy and Materials Sciences Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam ,India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Diksha J Baruah
- Materials Sciences Group, Coal, Energy and Materials Sciences Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam ,India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Rituparna Duarah
- Materials Sciences Group, Coal, Energy and Materials Sciences Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam ,India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Archana Yadav
- Centre for Biotechnology, Biological Sciences and Technology Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam ,India
| | - Dipjyoti Bora
- Materials Sciences Group, Coal, Energy and Materials Sciences Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam ,India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ratul Saikia
- Centre for Biotechnology, Biological Sciences and Technology Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam ,India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Jayaramudu Jarugala
- Materials Sciences Group, Coal, Energy and Materials Sciences Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam ,India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Manash R Das
- Materials Sciences Group, Coal, Energy and Materials Sciences Division, CSIR-North East Institute of Science and Technology, Jorhat 785006, Assam ,India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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Modi M, Chauhan D, Gilmore MC, Cava F, Priyadarshini R. Deficiency in peptidoglycan recycling promotes β-lactam sensitivity in Caulobacter crescentus. mBio 2025; 16:e0297524. [PMID: 40066998 PMCID: PMC11980594 DOI: 10.1128/mbio.02975-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2024] [Accepted: 02/07/2025] [Indexed: 04/10/2025] Open
Abstract
Peptidoglycan (PG)-modifying enzymes play a crucial role in cell wall remodeling, essential for growth and division. Cell wall degradation products are transported to the cytoplasm and recycled back in most gram-negative bacteria, and PG recycling is also linked to β-lactam resistance in many bacteria. Caulobacter crescentus is intrinsically resistant to β-lactams. Recently, it was shown that a soluble lytic transglycosylase, SdpA, is essential for β-lactam resistance. However, the precise role of SdpA in β-lactam resistance is unknown. This study investigated the PG recycling pathway and its role in antibiotic resistance in C. crescentus. Anhydromuropeptides generated by the action of lytic transglycosylases (LTs) are transported to the cytoplasm by the permease AmpG. C. crescentus encodes an ampG homolog, and deletion mutants of sdpA and ampG are sensitive to β-lactams. The ampG deletion mutant displays a significant accumulation of anhydromuropeptides in the periplasm of C. crescentus, demonstrating its essential role in PG recycling. While single knockout mutants of sdpA and ampG exhibit no growth defects, double-deletion mutants (∆sdpA∆ampG) exhibit severe growth and morphological defects. These double mutants also show enhanced sensitivity to β-lactams. Analysis of soluble muropeptides in wild-type (WT), ∆sdpA, and ∆ampG mutants revealed reduced levels of PG precursors (UDP-GlcNAc, UDP-MurNAc, and UDP-MurNAc-P5), suggesting that PG recycling products contribute toward de novo PG biosynthesis. Furthermore, supplementing the growth media with GlcNAc sugar enhanced the fitness of ∆sdpA and ∆ampG mutants under β-lactam stress. In conclusion, our study indicates that defects in PG recycling compromise cell wall biogenesis, leading to antibiotic sensitivity in C. crescentus.IMPORTANCEβ-lactam antibiotics target the peptidoglycan cell wall biosynthetic pathway in bacteria. In response to antibiotic pressures, bacteria have developed various resistance mechanisms. In many gram-negative species, cell wall degradation products are transported into the cytoplasm and induce the expression of β-lactamase enzymes. In this study, we investigated the cell wall recycling pathway and its role in antibiotic resistance in Caulobacter crescentus. Based on our data and prior studies, we propose that cell wall degradation products are utilized for the synthesis of peptidoglycan precursors in the cytoplasm. A deficiency in cell wall recycling leads to cell wall defects and increased antibiotic sensitivity in C. crescentus. These findings are crucial for understanding antibiotic resistance mechanisms in bacteria.
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Affiliation(s)
- Malvika Modi
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh, India
| | - Deepika Chauhan
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh, India
| | - Michael C. Gilmore
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Richa Priyadarshini
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh, India
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Chan V, Holcomb T, Kaspar JR, Shields RC. Characterization of MreCD in Streptococcus mutans. J Oral Microbiol 2025; 17:2487643. [PMID: 40206099 PMCID: PMC11980242 DOI: 10.1080/20002297.2025.2487643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2025] [Revised: 03/21/2025] [Accepted: 03/25/2025] [Indexed: 04/11/2025] Open
Abstract
Background Activities that control cell shape and division are critical for the survival of bacteria. However, little is known about the circuitry controlling these processes in the dental caries pathogen Streptococcus mutans. Methodology We designed experiments to characterize two genes, mreC and mreD, in S. mutans. Assays included cell morphology imaging, protein interaction analysis, transcriptomics, proteomics, and biofilm studies to generate a comprehensive understanding of the role of MreCD in S. mutans. Results Consistent with mreCD participating in cell elongation, cells lacking these genes were found to be rounder than wild-type cells. Using bacterial two-hybrid assays, interactions between MreCD and several other proteins implicated in cell elongation were observed. Further characterization, using proteomics, revealed that the surface-associated proteome is different in mutants lacking mreCD. Consistent with these changes we observed altered sucrose-mediated biofilm architecture. Loss of mreCD also had a noticeable impact on bacteriocin gene expression, which could account in part for the observation that mreCD mutants had a diminished capacity to compete with commensal streptococci. Conclusion Our results provide evidence that cell elongation proteins are required for normal S. mutans physiology and establish a foundation for additional examination of these and related proteins in this organism.
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Affiliation(s)
- Victor Chan
- Department of Oral Biology, University of Florida, Gainesville, FL, USA
| | - Tessa Holcomb
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, USA
| | - Justin R. Kaspar
- Division of Biosciences, Ohio State University, Columbus, OH, USA
| | - Robert C. Shields
- Department of Oral Biology, University of Florida, Gainesville, FL, USA
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, USA
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Palková Z, Váchová L. Cell differentiation, aging, and death in spatially organized yeast communities: mechanisms and consequences. Cell Death Differ 2025:10.1038/s41418-025-01485-9. [PMID: 40158069 DOI: 10.1038/s41418-025-01485-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 02/12/2025] [Accepted: 03/17/2025] [Indexed: 04/01/2025] Open
Abstract
Cell death is a natural part of the development of multicellular organisms and is central to their physiological and pathological states. However, the existence of regulated cell death in unicellular microorganisms, including eukaryotic and prokaryotic microbes, has been a topic of debate. One reason for the continued debate is the lack of obvious benefit from cell death in the context of a single cell. However, unicellularity is relative, as most of these microbes dwell in communities of varying complexities, often with complicated spatial organization. In these spatially organized microbial communities, such as yeast and bacterial colonies and biofilms growing on solid surfaces, cells differentiate into specialized types, and the whole community often behaves like a simple multicellular organism. As these communities develop and age, cell death appears to offer benefits to the community as a whole. This review explores the potential roles of cell death in spatially organized communities of yeasts and draws analogies to similar communities of bacteria. The natural dying processes in microbial cell communities are only partially understood and may result from suicidal death genes, (self-)sabotage (without death effectors), or from non-autonomous mechanisms driven by interactions with other differentiated cells. We focus on processes occurring during the stratification of yeast colonies, the formation of the extracellular matrix in biofilms, and discuss potential roles of cell death in shaping the organization, differentiation, and overall physiology of these microbial structures.
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Affiliation(s)
- Zdena Palková
- Department of Genetics and Microbiology, Faculty of Science, BIOCEV, Charles University, Prague, Czech Republic.
| | - Libuše Váchová
- Department of Genetics and Microbiology, Faculty of Science, BIOCEV, Charles University, Prague, Czech Republic
- Institute of Microbiology of the Czech Academy of Sciences, BIOCEV, Prague, Czech Republic
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Weaver AA, Shrout JD. Use of analytical strategies to understand spatial chemical variation in bacterial surface communities. J Bacteriol 2025; 207:e0040224. [PMID: 39873490 PMCID: PMC11841061 DOI: 10.1128/jb.00402-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2025] Open
Abstract
Not only do surface-growing microbes such as biofilms display specific traits compared to planktonic cells, but also they display many heterogeneous behaviors over many spatial and temporal contexts. While the application of molecular genetics tools to extract or visualize gene expression or regulatory function data is now common in studying surface growth, the use of analytical chemistry tools to visualize the spatiotemporal distribution of chemical products synthesized by these surface microbes is less common. Here, we review chemical imaging tools that have been used to inform our understanding of surface-growing microbes. We highlight the use of confocal Raman Microscopy, surface-enhanced Raman spectroscopy, matrix-assisted laser desorption/ionization, secondary ion mass spectrometry, desorption electrospray ionization, and electrochemical imaging that have been applied to assess two-dimensional chemical profiles of bacteria. We specifically discuss the use of these tools to study rhamnolipids, alkylquinolones, and phenazines of the bacterium Pseudomonas aeruginosa.
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Affiliation(s)
- Abigail A. Weaver
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Joshua D. Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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Zhang Y, He P, Hu S, Zhang R, Asfandyar, Chen S. Overexpressing Endopeptidase Inhibitor IseA Enhances Biomass and Biochemical Production of Bacillus licheniformis. Curr Microbiol 2025; 82:116. [PMID: 39903300 DOI: 10.1007/s00284-025-04096-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Accepted: 01/21/2025] [Indexed: 02/06/2025]
Abstract
Cell autolysis could lead to a decrease in both cell viability and the production of biochemicals, presenting one of the significant challenges during fermentation. Bacillus licheniformis, a gram-positive bacterium widely used in the production of various biologic products, also confronts the limitation caused by cell autolysis. In this study, we investigated the impact of peptidoglycan hydrolases (LytC, LytD, LytE, CwlC), endopeptidase inhibitor IseA, and prophage gene xpf on cell growth and biochemical synthesis in B. licheniformis DW2. The results showed that the deletion of xpf and overexpression of iseA could significantly increase cell survival. Then, xpf was deleted on iseA overexpressed strain PP43UTR12iseA to construct engineered strain PP43UTR12iseAΔxpf, which further enhanced viable cells. The results of cell autolysis showed that PP43UTR12iseA could reduce cell autolysis significantly compared to the wild-type, but PP43UTR12iseAΔxpf did not further decrease cell autolysis. Furthermore, the production of bacitracin was 792.23 U/mL in the iseA overexpressed strain, which increased by 13.82% compared with the wild-type, but PP43UTR12iseAΔxpf did not further increase bacitracin production. Through detecting intracellular metabolites, we observed that iseA overexpression did not affect intracellular metabolism, but the precursors of bacitracin synthesis in PP43UTR12iseAΔxpf were lower than that of wild-type and PP43UTR12iseA. Finally, we found that the overexpression of iseA could also significantly improve the production of γ-PGA. In general, the overexpression of iseA could enhance the biomass and cell survival by reducing cell lysis without affecting the intracellular metabolites, which provided a potential strategy to improve production of biochemical.
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Affiliation(s)
- Yongjia Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, China
| | - Penghui He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, China
| | - Shiying Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, China
| | - Ruibin Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, China
| | - Asfandyar
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, China
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, China.
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Goh SM, Dassanayake MK, Foan CC, Wiart C, Symonds R, Khoo TJ, Chong CH, Elfar OA. Antibacterial potency of mid-polar extracts obtained from Malaysian plant Parkia speciosa against human pathogenic bacteria. Microb Pathog 2025; 198:107134. [PMID: 39566830 DOI: 10.1016/j.micpath.2024.107134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 11/12/2024] [Accepted: 11/18/2024] [Indexed: 11/22/2024]
Abstract
BACKGROUND AND OBJECTIVES Plants contain a wide variety of bioactive compounds, which have attracted the interest of researchers in finding novel sources of natural medicine. In the following paper, we aim to evaluate the antibacterial potential of extract fractions associated with Parkia speciosa pods and beans against human pathogenic bacteria. METHODS Antimicrobial activity was determined with disc diffusion and broth microdilution assays against eight skin colonising microorganisms including Staphylococcus aureus, Staphylococcus epidermidis, Salmonella enterica, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia followed by further fractionation of the pods ethyl acetate fraction by column chromatography along with preparative thin-layer chromatography. Quantification of bacterial death mechanism was elucidated by the measurement of hole size in cell wall that has been induced by extract constituents via field-emission scanning electron microscopy (FESEM). RESULTS Four fractions showed significant antimicrobial activity against the six microorganisms tested (p < 0.01), with inhibition zones ranging from 35.67 to 17.00 mm, and minimum inhibitory concentration ranging from 6.25 to 50.00 mg/ml in which the pods ethyl acetate fraction was the most effective. The methanol fraction isolated from the pods ethyl acetate fraction was much more effective with a four-fold increase from 6.25 to 1.25 mg/ml against S. epidermidis. The disintegration of S. aureus was due to chronic cell wall alterations with pore creation, invaginations and morphological disorganisation. Autolysis in bacterial cells via the expression of peptidoglycan-disrupting lysozyme or bacterial murein hydrolase was postulated. A significantly large pore with a mean diameter of 293.7 nm was detected in the cell wall of S. aureus. CONCLUSION P. speciosa fraction could be a potential novel source for the development of a natural antibacterial agent.
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Affiliation(s)
- She May Goh
- School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500, Malaysia
| | - Mackingsley Kushan Dassanayake
- School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500, Malaysia.
| | - Chin Chiew Foan
- School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500, Malaysia
| | - Christophe Wiart
- Institute of Tropical Biology and Conservation, University Malaysia Sabah, 88400, Jalan Sulaman, Kota Kinabalu, Sabah, Malaysia
| | - Rachael Symonds
- School of Biological and Environmental Sciences, Faculty of Science, Liverpool John Moores University, James Parsons Building, Byrom St, Liverpool, L3 3AF, United Kingdom
| | - Teng-Jin Khoo
- School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500, Malaysia.
| | - Chien Hwa Chong
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500, Malaysia
| | - Omar Ashraf Elfar
- School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500, Malaysia
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10
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Torrens G, Cava F. Mechanisms conferring bacterial cell wall variability and adaptivity. Biochem Soc Trans 2024; 52:1981-1993. [PMID: 39324635 PMCID: PMC11555704 DOI: 10.1042/bst20230027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2024] [Revised: 08/28/2024] [Accepted: 08/30/2024] [Indexed: 09/27/2024]
Abstract
The bacterial cell wall, a sophisticated and dynamic structure predominantly composed of peptidoglycan (PG), plays a pivotal role in bacterial survival and adaptation. Bacteria actively modify their cell walls by editing PG components in response to environmental challenges. Diverse variations in peptide composition, cross-linking patterns, and glycan strand structures empower bacteria to resist antibiotics, evade host immune detection, and adapt to dynamic environments. This review comprehensively summarizes the most common modifications reported to date and their associated adaptive role and further highlights how regulation of PG synthesis and turnover provides resilience to cell lysis.
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Affiliation(s)
- Gabriel Torrens
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
| | - Felipe Cava
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
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Hu B, Gao S, Zhang H, Li Q, Li G, Zhang S, Xing Y, Huang Y, Han S, Tian Y, Zhang W, He H. Whole-genome sequencing and pathogenicity analysis of Rhodococcus equi isolated in horses. BMC Vet Res 2024; 20:362. [PMID: 39129003 PMCID: PMC11318318 DOI: 10.1186/s12917-024-04167-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 07/01/2024] [Indexed: 08/13/2024] Open
Abstract
BACKGROUND Rhodococcus equi (R. equi) is a Gram-positive zoonotic pathogen that frequently leads to illness and death in young horses (foals). This study presents the complete genome sequence of R. equi strain BJ13, which was isolated from a thoroughbred racehorse breeding farm in Beijing, China. RESULTS The BJ13 genome has a length of 5.30 Mb and consists of a complete chromosome and a plasmid measuring 5.22 Mb and 0.08 Mb, respectively. We predicted 4,929 coding gene open reading frames, along with 52 tRNAs and 12 rRNAs. Through analysis of mobile genetic elements, we identified 6 gene islands and 1 prophage gene. Pathogenic system analysis predicted the presence of 418 virulence factors and 225 drug resistance genes. Secretion system analysis revealed the prediction of 297 secreted proteins and 1,106 transmembrane proteins. BJ13 exhibits genomic features, virulence-associated genes, potential drug resistance, and a virulence plasmid structure that may contribute to the evolution of its pathogenicity. Lastly, the pathogenicity of the isolated strain was assessed through animal experiments, which resulted in inflammatory reactions or damage in the lungs, liver, and spleen of mice. Moreover, by the 7th day post-infection, the mortality rate of the mice reached 50.0%, indicating complex immune regulatory mechanisms, including overexpression of IL-10 and increased production of pro-inflammatory cytokines like TNF-α. These findings validate the strong pathogenicity of the isolated strain and provide insights for studying the pathogenic mechanisms of Rhodococcus equi infection. CONCLUSIONS The complete genome sequence of R. equi strain BJ13 provides valuable insights into its genomic characteristics, virulence potential, drug resistance, and secretion systems. The strong pathogenicity observed in animal experiments underscores the need for further investigation into the pathogenic mechanisms of R. equi infection.
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Affiliation(s)
- Bin Hu
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang, China
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Sichao Gao
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Anhui University of Science and Technology, Huainan, China
| | - Hao Zhang
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiaoqiao Li
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Anhui University of Science and Technology, Huainan, China
| | - Gaojian Li
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shuairan Zhang
- College of Shenyang Institute of Technology, Shenyang, Liaoning, China
| | - Yanan Xing
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yanyi Huang
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shuyi Han
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ying Tian
- Beijing Wildlife Rescue and Rehabilitation Center, Beijing, China
| | - Wei Zhang
- Beijing Wildlife Rescue and Rehabilitation Center, Beijing, China
| | - Hongxuan He
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang, China.
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12
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Weaver AA, Jia J, Cutri AR, Madukoma CS, Vaerewyck CM, Bohn PW, Shrout JD. Alkyl quinolones mediate heterogeneous colony biofilm architecture that improves community-level survival. J Bacteriol 2024; 206:e0009524. [PMID: 38564677 PMCID: PMC11025328 DOI: 10.1128/jb.00095-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 03/11/2024] [Indexed: 04/04/2024] Open
Abstract
Bacterial communities exhibit complex self-organization that contributes to their survival. To better understand the molecules that contribute to transforming a small number of cells into a heterogeneous surface biofilm community, we studied acellular aggregates, structures seen by light microscopy in Pseudomonas aeruginosa colony biofilms using light microscopy and chemical imaging. These structures differ from cellular aggregates, cohesive clusters of cells important for biofilm formation, in that they are visually distinct from cells using light microscopy and are reliant on metabolites for assembly. To investigate how these structures benefit a biofilm community we characterized three recurrent types of acellular aggregates with distinct geometries that were each abundant in specific areas of these biofilms. Alkyl quinolones (AQs) were essential for the formation of all aggregate types with AQ signatures outside the aggregates below the limit of detection. These acellular aggregates spatially sequester AQs and differentiate the biofilm space. However, the three types of aggregates showed differing properties in their size, associated cell death, and lipid content. The largest aggregate type co-localized with spatially confined cell death that was not mediated by Pf4 bacteriophage. Biofilms lacking AQs were absent of localized cell death but exhibited increased, homogeneously distributed cell death. Thus, these AQ-rich aggregates regulate metabolite accessibility, differentiate regions of the biofilm, and promote survival in biofilms.IMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen with the ability to cause infection in the immune-compromised. It is well established that P. aeruginosa biofilms exhibit resilience that includes decreased susceptibility to antimicrobial treatment. This work examines the self-assembled heterogeneity in biofilm communities studying acellular aggregates, regions of condensed matter requiring alkyl quinolones (AQs). AQs are important to both virulence and biofilm formation. Aggregate structures described here spatially regulate the accessibility of these AQs, differentiate regions of the biofilm community, and despite their association with autolysis, correlate with improved P. aeruginosa colony biofilm survival.
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Affiliation(s)
- Abigail A. Weaver
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Jin Jia
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Allison R. Cutri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Chinedu S. Madukoma
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Catherine M. Vaerewyck
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Paul W. Bohn
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana, USA
| | - Joshua D. Shrout
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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13
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Modi M, Thambiraja M, Cherukat A, Yennamalli RM, Priyadarshini R. Structure predictions and functional insights into Amidase_3 domain containing N-acetylmuramyl-L-alanine amidases from Deinococcus indicus DR1. BMC Microbiol 2024; 24:101. [PMID: 38532329 DOI: 10.1186/s12866-024-03225-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 02/15/2024] [Indexed: 03/28/2024] Open
Abstract
BACKGROUND N-acetylmuramyl-L-alanine amidases are cell wall modifying enzymes that cleave the amide bond between the sugar residues and stem peptide in peptidoglycan. Amidases play a vital role in septal cell wall cleavage and help separate daughter cells during cell division. Most amidases are zinc metalloenzymes, and E. coli cells lacking amidases grow as chains with daughter cells attached to each other. In this study, we have characterized two amidase enzymes from Deinococcus indicus DR1. D. indicus DR1 is known for its high arsenic tolerance and unique cell envelope. However, details of their cell wall biogenesis remain largely unexplored. RESULTS We have characterized two amidases Ami1Di and Ami2Di from D. indicus DR1. Both Ami1Di and Ami2Di suppress cell separation defects in E. coli amidase mutants, suggesting that these enzymes are able to cleave septal cell wall. Ami1Di and Ami2Di proteins possess the Amidase_3 catalytic domain with conserved -GHGG- motif and Zn2+ binding sites. Zn2+- binding in Ami1Di is crucial for amidase activity. AlphaFold2 structures of both Ami1Di and Ami2Di were predicted, and Ami1Di was a closer homolog to AmiA of E. coli. CONCLUSION Our results indicate that Ami1Di and Ami2Di enzymes can cleave peptidoglycan, and structural prediction studies revealed insights into the activity and regulation of these enzymes in D. indicus DR1.
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Affiliation(s)
- Malvika Modi
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh, 201314, India
| | - Menaka Thambiraja
- Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamil Nadu, 613401, India
| | - Archana Cherukat
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh, 201314, India
- Department of Biology, Graduate School of Arts and Sciences, Wake Forest University, 1834 Wake Forest Rd, Winston-Salem, USA
| | - Ragothaman M Yennamalli
- Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamil Nadu, 613401, India
| | - Richa Priyadarshini
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh, 201314, India.
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Gurbatri C, Danino T. Engineering Probiotic E. coli Nissle 1917 for Release of Therapeutic Nanobodies. Methods Mol Biol 2024; 2748:289-305. [PMID: 38070121 DOI: 10.1007/978-1-0716-3593-3_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Bioengineered probiotics enable new opportunities to improve cancer treatment strategies due to their tumor-colonizing capabilities. Here, we will describe the development of a probiotic E. coli Nissle 1917 platform encoding a synchronized lysis mechanism for the localized and sustained release of blocking nanobodies against immune checkpoint molecules like programmed cell death protein-ligand 1 and cytotoxic T lymphocyte-associated protein-4. Specifically, we will detail the experimental protocols needed to (1) encode and validate binding of recombinantly produced checkpoint blockade nanobodies, (2) evaluate the therapeutic efficacy and safety of the probiotic platform in syngeneic tumor-bearing mice, and (3) analyze the immunophenotype of the tumor microenvironment.
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Affiliation(s)
- Candice Gurbatri
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Tal Danino
- Department of Biomedical Engineering, Columbia University, New York, NY, USA.
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15
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Gouveia A, Pinto D, Vítor JMB, São-José C. Cellular and Enzymatic Determinants Impacting the Exolytic Action of an Anti-Staphylococcal Enzybiotic. Int J Mol Sci 2023; 25:523. [PMID: 38203699 PMCID: PMC10778630 DOI: 10.3390/ijms25010523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
Bacteriophage endolysins are bacteriolytic enzymes that have been explored as potential weapons to fight antibiotic-resistant bacteria. Despite several studies support the application of endolysins as enzybiotics, detailed knowledge on cellular and enzymatic factors affecting their lytic activity is still missing. The bacterial membrane proton motive force (PMF) and certain cell wall glycopolymers of Gram-positive bacteria have been implicated in some tolerance to endolysins. Here, we studied how the anti-staphylococcal endolysin Lys11, a modular enzyme with two catalytic domains (peptidase and amidase) and a cell binding domain (CBD11), responded to changes in the chemical and/or electric gradients of the PMF (ΔpH and Δψ, respectively). We show that simultaneous dissipation of both gradients enhances endolysin binding to cells and lytic activity. The collapse of ΔpH is preponderant in the stimulation of Lys11 lytic action, while the dissipation of Δψ is mainly associated with higher endolysin binding. Interestingly, this binding depends on the amidase domain. The peptidase domain is responsible for most of the Lys11 bacteriolytic activity. Wall teichoic acids (WTAs) are confirmed as major determinants of endolysin tolerance, in part by severely hindering CBD11 binding activity. In conclusion, the PMF and WTA interfere differently with the endolysin functional domains, affecting both the binding and catalytic efficiencies.
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Affiliation(s)
- Ana Gouveia
- Phage Biology Research and Infection Control (PhaBRIC), Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (A.G.); (D.P.)
| | - Daniela Pinto
- Phage Biology Research and Infection Control (PhaBRIC), Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (A.G.); (D.P.)
| | - Jorge M. B. Vítor
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal;
| | - Carlos São-José
- Phage Biology Research and Infection Control (PhaBRIC), Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (A.G.); (D.P.)
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16
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Lee E, Kim D, Seo H, Hahm J, Seo J, Lee S, Kim D, Ahn J, Jung CH. Akkermansia muciniphila promotes testosterone-mediated hair growth inhibition in mice. FASEB Bioadv 2023; 5:521-527. [PMID: 38094156 PMCID: PMC10714060 DOI: 10.1096/fba.2023-00056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 10/16/2024] Open
Abstract
The beneficial effects of Akkermansia muciniphila (Akk) on gut health and inflammation reduction have been demonstrated; however, scientific evidence of hair growth enhancement by Akk has not been reported. Therefore, this study was undertaken to investigate the effect of Akk on improving testosterone-mediated hair growth inhibition. Hair growth inhibition was induced through subcutaneous injection of testosterone into the shaved dorsal skin of C57BL/6 male mice. Live and pasteurized Akk were orally administered at a concentration of 1 × 108 colony-forming unit. After 5 weeks, hair length and skin tissues were analyzed. The live and pasteurized Akk significantly stimulated hair growth, countering the inhibitory effect of testosterone compared to the testosterone-alone group. Hematoxylin and eosin staining revealed a significant increase in hair follicle size in the Akk-treated group. An increase in β-catenin levels, which are associated with hair growth and cell cycle progression, was also observed. Moreover, the Akk-treated group exhibited increased levels of fibroblast growth factors, including Fgf7, Igf1, Fgf7, Fgf10, and Fgf21. However, no significant difference was observed between the live and pasteurized Akk groups. These results underscore the potential of live and pasteurized Akk in improving testosterone-mediated hair growth inhibition.
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Affiliation(s)
- Eunyoung Lee
- Aging and Metabolism Research GroupKorea Food Research InstituteWanju‐gunJeollabuk‐doRepublic of Korea
| | - Daedong Kim
- Aging and Metabolism Research GroupKorea Food Research InstituteWanju‐gunJeollabuk‐doRepublic of Korea
- Department of Food BiotechnologyUniversity of Science and TechnologyWanju‐gunJeollabuk‐doRepublic of Korea
| | - Hyo‐Deok Seo
- Aging and Metabolism Research GroupKorea Food Research InstituteWanju‐gunJeollabuk‐doRepublic of Korea
| | - Jeong‐Hoon Hahm
- Aging and Metabolism Research GroupKorea Food Research InstituteWanju‐gunJeollabuk‐doRepublic of Korea
| | - Jae‐Gu Seo
- R&D centerEnterobiome Inc.Goyang‐siRepublic of Korea
| | - Sang‐Nam Lee
- R&D centerEnterobiome Inc.Goyang‐siRepublic of Korea
| | - Do‐Hak Kim
- R&D centerEnterobiome Inc.Goyang‐siRepublic of Korea
| | - Jiyun Ahn
- Aging and Metabolism Research GroupKorea Food Research InstituteWanju‐gunJeollabuk‐doRepublic of Korea
- Department of Food BiotechnologyUniversity of Science and TechnologyWanju‐gunJeollabuk‐doRepublic of Korea
| | - Chang Hwa Jung
- Aging and Metabolism Research GroupKorea Food Research InstituteWanju‐gunJeollabuk‐doRepublic of Korea
- Department of Food BiotechnologyUniversity of Science and TechnologyWanju‐gunJeollabuk‐doRepublic of Korea
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17
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Gómez-Arrebola C, Hernandez SB, Culp EJ, Wright GD, Solano C, Cava F, Lasa I. Staphylococcus aureus susceptibility to complestatin and corbomycin depends on the VraSR two-component system. Microbiol Spectr 2023; 11:e0037023. [PMID: 37646518 PMCID: PMC10581084 DOI: 10.1128/spectrum.00370-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 06/30/2023] [Indexed: 09/01/2023] Open
Abstract
The overuse of antibiotics in humans and livestock has driven the emergence and spread of antimicrobial resistance and has therefore prompted research on the discovery of novel antibiotics. Complestatin (Cm) and corbomycin (Cb) are glycopeptide antibiotics with an unprecedented mechanism of action that is active even against methicillin-resistant and daptomycin-resistant Staphylococcus aureus. They bind to peptidoglycan and block the activity of peptidoglycan hydrolases required for remodeling the cell wall during growth. Bacterial signaling through two-component transduction systems (TCSs) has been associated with the development of S. aureus antimicrobial resistance. However, the role of TCSs in S. aureus susceptibility to Cm and Cb has not been previously addressed. In this study, we determined that, among all 16 S. aureus TCSs, VraSR is the only one controlling the susceptibility to Cm and Cb. Deletion of vraSR increased bacterial susceptibility to both antibiotics. Epistasis analysis with members of the vraSR regulon revealed that deletion of spdC, which encodes a membrane protein that scaffolds SagB for cleavage of peptidoglycan strands to achieve physiological length, in the vraSR mutant restored Cm and Cb susceptibility to wild-type levels. Moreover, deletion of either spdC or sagB in the wild-type strain increased resistance to both antibiotics. Further analyses revealed a significant rise in the relative amount of peptidoglycan and its total degree of cross-linkage in ΔspdC and ΔsagB mutants compared to the wild-type strain, suggesting that these changes in the cell wall provide resistance to the damaging effect of Cm and Cb. IMPORTANCE Although Staphylococcus aureus is a common colonizer of the skin and digestive tract of humans and many animals, it is also a versatile pathogen responsible for causing a wide variety and number of infections. Treatment of these infections requires the bacteria to be constantly exposed to antibiotic treatment, which facilitates the selection of antibiotic-resistant strains. The development of new antibiotics is, therefore, urgently needed. In this paper, we investigated the role of the sensory system of S. aureus in susceptibility to two new antibiotics: corbomycin and complestatin. The results shed light on the cell-wall synthesis processes that are affected by the presence of the antibiotic and the sensory system responsible for coordinating their activity.
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Affiliation(s)
- Carmen Gómez-Arrebola
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Sara B. Hernandez
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Elizabeth J. Culp
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Gerard D. Wright
- Department of Biochemistry and Biomedical Sciences, M. G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Cristina Solano
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
| | - Felipe Cava
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Iñigo Lasa
- Laboratory of Microbial Pathogenesis, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain
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Liu S, Wang P, Wang C, Chen J, Wang X, Hu B, Shan X. Disparate toxicity mechanisms of parabens with different alkyl chain length in freshwater biofilms: Ecological hazards associated with antibiotic resistome. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 881:163168. [PMID: 37003345 DOI: 10.1016/j.scitotenv.2023.163168] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 03/15/2023] [Accepted: 03/26/2023] [Indexed: 06/01/2023]
Abstract
As emerging organic pollutants, parabens are of global concern because of their ubiquitous presence and adverse effects. However, few researchers have addressed the relationship between parabens' structural features and toxicity mechanisms. This study conducted theoretical calculations and laboratory exposure experiments to uncover the toxic effects and mechanisms of parabens with different alkyl chains in freshwater biofilms. The result demonstrated that parabens' hydrophobicity and lethality increased with their alkyl-chain length, whereas the possibility of chemical reactions and reactive sites were unchanged despite the alkyl-chain length alteration. Due to the hydrophobicity variation, parabens with different alkyl-chain presented different distribution patterns in cells of freshwater biofilms and consequently induced distinct toxic effects and led to diverse cell death modes. The butylparaben with longer alkyl-chain preferred to stay in the membrane and altered membrane permeability by non-covalent interaction with phospholipid, which caused cell necrosis. The methylparaben with shorter alkyl-chain preferred to enter into the cytoplasm and influence mazE gene expression by chemically reacting with biomacromolecules, thereby triggering apoptosis. The different cell death patterns induced by parabens contributed to different ecological hazards associated with antibiotic resistome. Compared with butylparaben, methylparaben was more likely to spread ARGs among microbial communities despite its lower lethality.
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Affiliation(s)
- Sheng Liu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China; School of Civil Engineering, Shandong University, Jinan 250061, China
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
| | - Chao Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Juan Chen
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Xun Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Bin Hu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Xiaorong Shan
- Sid and Reva Dewberry Dept. of Civil, Environmental, & Infrastructure Engineering, George Mason University, Fairfax, VA, USA
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Ikryannikova LN, Gorokhovets NV, Belykh DA, Kurbatov LK, Zamyatnin AA. Bacterial Therapy of Cancer: A Way to the Dustbin of History or to the Medicine of the Future? Int J Mol Sci 2023; 24:ijms24119726. [PMID: 37298677 DOI: 10.3390/ijms24119726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 05/23/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Bacteria are the constant companions of the human body throughout its life and even after its death. The history of a human disease such as cancer and the history of microorganisms, particularly bacteria, are believed to closely intertwined. This review was conceived to highlight the attempts of scientists from ancient times to the present day to discover the relationship between bacteria and the emergence or development of tumors in the human body. Challenges and achievements of 21st century science in forcing bacteria to serve for cancer treatment are considered. The future possibilities of bacterial cancer therapy, including the creation of bacterial microrobots, or "bacteriobots", are also discussed.
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Affiliation(s)
- Larisa N Ikryannikova
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya 8/2, 119991 Moscow, Russia
| | - Neonila V Gorokhovets
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya 8/2, 119991 Moscow, Russia
| | - Darya A Belykh
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya 8/2, 119991 Moscow, Russia
| | - Leonid K Kurbatov
- Orekhovich Research Institute of Biomedical Chemistry, Pogodinskaya 10/8, 119991 Moscow, Russia
| | - Andrey A Zamyatnin
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya 8/2, 119991 Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Leninskie Gory 1/73, 119234 Moscow, Russia
- Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1/40, 119992 Moscow, Russia
- Scientific Center for Translation Medicine, Sirius University of Science and Technology, 1 Olympic Ave, 354340 Sochi, Russia
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Bosnar LM, Shindler AE, Wood J, Patch C, Franks AE. Attempts to limit sporulation in the probiotic strain Bacillus subtilis BG01-4 TM through mutation accumulation and selection. Access Microbiol 2023; 5:acmi000419. [PMID: 37323944 PMCID: PMC10267654 DOI: 10.1099/acmi.0.000419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/16/2023] [Indexed: 06/17/2023] Open
Abstract
The use of bacterial spores in probiotics over viable loads of bacteria has many advantages, including the durability of spores, which allows spore-based probiotics to effectively traverse the various biochemical barriers present in the gastrointestinal tract. However, the majority of spore-based probiotics developed currently aim to treat adults, and there is a litany of differences between the adult and infant intestinal systems, including the immaturity and low microbial species diversity observed within the intestines of infants. These differences are only further exacerbated in premature infants with necrotizing enterocolitis (NEC) and indicates that what may be appropriate for an adult or even a healthy full-term infant may not be suited for an unhealthy premature infant. Complications from using spore-based probiotics for premature infants with NEC may involve the spores remaining dormant and adhering to the intestinal epithelia, the out-competing of commensal bacteria by spores, and most importantly the innate antibiotic resistance of spores. Also, the ability of Bacillus subtilis to produce spores under duress may result in less B. subtilis perishing within the intestines and releasing membrane branched-chain fatty acids. The isolate B. subtilis BG01-4TM is a proprietary strain developed by Vernx Biotechnology through accumulating mutations within the BG01-4TM genome in a serial batch culture. Strain BG01-4TM was provided as a non-spore-forming B. subtilis , but a positive sporulation status for BG01-4TM was confirmed through in vitro testing and suggested that selection for the sporulation defective genes could occur within an environment that would select against sporulation. The durability of key sporulation genes was ratified in this study, as the ability of BG01-4TM to produce spores was not eliminated by the attempts to select against sporulation genes in BG01-4TM by the epigenetic factors of high glucose and low pH. However, a variation in the genes in isolate BG01-4-8 involved in the regulation of sporulation is believed to have occurred during the mutation selection from the parent strain BG01-4TM. An alteration in selected sporulation regulation genes is expected to have occurred from BG01-4TM to BG01-4-8, with BG01-4-8 producing spores within 24 h, ~48 h quicker than BG01-4TM.
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Affiliation(s)
- Luke M. Bosnar
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Anya E. Shindler
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Jennifer Wood
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Craig Patch
- School of Allied Health, Human Services, and Sport, La Trobe University, Melbourne, Victoria 3086, Australia
- Vernx Pty Ltd, Level 17, 40 City Road, Southbank, Victoria 3066, Australia
| | - Ashley E. Franks
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
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21
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Giallonardi G, Letizia M, Mellini M, Frangipani E, Halliday N, Heeb S, Cámara M, Visca P, Imperi F, Leoni L, Williams P, Rampioni G. Alkyl-quinolone-dependent quorum sensing controls prophage-mediated autolysis in Pseudomonas aeruginosa colony biofilms. Front Cell Infect Microbiol 2023; 13:1183681. [PMID: 37305419 PMCID: PMC10250642 DOI: 10.3389/fcimb.2023.1183681] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Pseudomonas aeruginosa is a model quorum sensing (QS) pathogen with three interconnected QS circuits that control the production of virulence factors and antibiotic tolerant biofilms. The pqs QS system of P. aeruginosa is responsible for the biosynthesis of diverse 2-alkyl-4-quinolones (AQs), of which 2-heptyl-4-hydroxyquinoline (HHQ) and 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS) function as QS signal molecules. Transcriptomic analyses revealed that HHQ and PQS influenced the expression of multiple genes via PqsR-dependent and -independent pathways whereas 2-heptyl-4-hydroxyquinoline N-oxide (HQNO) had no effect on P. aeruginosa transcriptome. HQNO is a cytochrome bc 1 inhibitor that causes P. aeruginosa programmed cell death and autolysis. However, P. aeruginosa pqsL mutants unable to synthesize HQNO undergo autolysis when grown as colony biofilms. The mechanism by which such autolysis occurs is not understood. Through the generation and phenotypic characterization of multiple P. aeruginosa PAO1 mutants producing altered levels of AQs in different combinations, we demonstrate that mutation of pqsL results in the accumulation of HHQ which in turn leads to Pf4 prophage activation and consequently autolysis. Notably, the effect of HHQ on Pf4 activation is not mediated via its cognate receptor PqsR. These data indicate that the synthesis of HQNO in PAO1 limits HHQ-induced autolysis mediated by Pf4 in colony biofilms. A similar phenomenon is shown to occur in P. aeruginosa cystic fibrosis (CF) isolates, in which the autolytic phenotype can be abrogated by ectopic expression of pqsL.
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Affiliation(s)
| | | | - Marta Mellini
- Department of Science, University Roma Tre, Rome, Italy
| | | | - Nigel Halliday
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Stephan Heeb
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Miguel Cámara
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Paolo Visca
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
| | - Francesco Imperi
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
| | - Livia Leoni
- Department of Science, University Roma Tre, Rome, Italy
| | - Paul Williams
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Giordano Rampioni
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
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22
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Ke L, Wang J, Liu Y, Sun Z, Li Y, Xiao X. Identification of the antibacterial action mechanism of curcumin on Streptococcus mutans through transcriptome profiling. Arch Oral Biol 2023; 149:105655. [PMID: 36842372 DOI: 10.1016/j.archoralbio.2023.105655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/11/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023]
Abstract
OBJECTIVE The purpose of this study was to explore the effect and mechanism responsible for how curcumin affects the biofilm formation by Streptococcus mutans (S. mutans). DESIGN The antibacterial activity of curcumin was evaluated by measuring the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The mass of the biofilm was measured by crystal violet staining. Transcriptome sequencing was used to obtain all the transcript information associated with the biological activity of curcumin-treated S. mutans. Real-time quantitative PCR (qRT-PCR) was performed to examine the expression levels of related biofilm formation genes. RESULTS The MIC value for curcumin was 64 μM. Curcumin inhibited the formation of a biofilm by S. mutans and degraded mature biofilms. A gene ontology enrichment analysis showed that the DEGs were significantly relevant to biofilm formation. In addition, 17 significantly enriched Kyoto Encyclopedia of Genes and Genomes pathways (p ≤ 0.01) were identified and were potentially associated with the biochemical metabolic processes of S. mutans. DEGs associated with the biofilm formation of S. mutants, including gtfB, gtfC, rgpG, spaP, spxA1, spxA2, bacA, lrgB, and gshAB. The qRT-PCR results were consistent with transcriptome sequencing that the expression levels of gtfB, gtfC, rgpG, and spaP significantly decreased in the curcumin-treated group, whereas the expression levels of spx1, spx2, bacA, lrgB, and gshAB were up-regulated. CONCLUSIONS Curcumin showed marked inhibitory effects against the formation of biofilms by S. mutans and degradation of formed biofilms.
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Affiliation(s)
- Li Ke
- Department of Critical Care Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China.
| | - Jiajun Wang
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China; Hubei Engineering Center for Infectious Disease Prevention, Control and Treatment, Wuhan, China; Wuhan Research Center for Infectious Diseases and Tumors of the Chinese Academy of Medical Science, Wuhan, China.
| | - Yanhua Liu
- Department of clinical laboratory, Hospital of China University of Geosciences, Wuhan, China.
| | - Zhongyi Sun
- Department of Critical Care Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China.
| | - Yirong Li
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China; Hubei Engineering Center for Infectious Disease Prevention, Control and Treatment, Wuhan, China; Wuhan Research Center for Infectious Diseases and Tumors of the Chinese Academy of Medical Science, Wuhan, China.
| | - Xiao Xiao
- Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China; Hubei Engineering Center for Infectious Disease Prevention, Control and Treatment, Wuhan, China; Wuhan Research Center for Infectious Diseases and Tumors of the Chinese Academy of Medical Science, Wuhan, China.
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23
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Karnwal A, Kumar G, Pant G, Hossain K, Ahmad A, Alshammari MB. Perspectives on Usage of Functional Nanomaterials in Antimicrobial Therapy for Antibiotic-Resistant Bacterial Infections. ACS OMEGA 2023; 8:13492-13508. [PMID: 37091369 PMCID: PMC10116640 DOI: 10.1021/acsomega.3c00110] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/28/2023] [Indexed: 05/03/2023]
Abstract
The clinical applications of nanotechnology are emerging as widely popular, particularly as a potential treatment approach for infectious diseases. Diseases associated with multiple drug-resistant organisms (MDROs) are a global concern of morbidity and mortality. The prevalence of infections caused by antibiotic-resistant bacterial strains has increased the urgency associated with researching and developing novel bactericidal medicines or unorthodox methods capable of combating antimicrobial resistance. Nanomaterial-based treatments are promising for treating severe bacterial infections because they bypass antibiotic resistance mechanisms. Nanomaterial-based approaches, especially those that do not rely on small-molecule antimicrobials, display potential since they can bypass drug-resistant bacteria systems. Nanoparticles (NPs) are small enough to pass through the cell membranes of pathogenic bacteria and interfere with essential molecular pathways. They can also target biofilms and eliminate infections that have proven difficult to treat. In this review, we described the antibacterial mechanisms of NPs against bacteria and the parameters involved in targeting established antibiotic resistance and biofilms. Finally, yet importantly, we talked about NPs and the various ways they can be utilized, including as delivery methods, intrinsic antimicrobials, or a mixture.
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Affiliation(s)
- Arun Karnwal
- Department
of Microbiology, School of Bioengineering & Biosciences, Lovely Professional University, Phagwara, Punjab 144411, India
| | - Gaurav Kumar
- Department
of Microbiology, School of Bioengineering & Biosciences, Lovely Professional University, Phagwara, Punjab 144411, India
| | - Gaurav Pant
- Department
of Microbiology, Graphic Era (Deemed to
be University), Dehradun, Uttarakhand 248002, India
| | - Kaizar Hossain
- Department
of Environmental Science, Asutosh College, University of Calcutta, 92, Shyama Prasad Mukherjee Road, Bhowanipore, Kolkata 700026, West
Bengal, India
| | - Akil Ahmad
- Department
of Chemistry, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
| | - Mohammed B. Alshammari
- Department
of Chemistry, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
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24
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Brogan AP, Rudner DZ. Regulation of peptidoglycan hydrolases: localization, abundance, and activity. Curr Opin Microbiol 2023; 72:102279. [PMID: 36812681 PMCID: PMC10031507 DOI: 10.1016/j.mib.2023.102279] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 02/22/2023]
Abstract
Most bacteria are surrounded by a cell wall composed of peptidoglycan (PG) that specifies shape and protects the cell from osmotic rupture. Growth, division, and morphogenesis are intimately linked to the synthesis of this exoskeleton but also its hydrolysis. The enzymes that cleave the PG meshwork require careful control to prevent aberrant hydrolysis and loss of envelope integrity. Bacteria employ diverse mechanisms to control the activity, localization, and abundance of these potentially autolytic enzymes. Here, we discuss four examples of how cells integrate these control mechanisms to finely tune cell wall hydrolysis. We highlight recent advances and exciting avenues for future investigation.
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Affiliation(s)
- Anna P Brogan
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - David Z Rudner
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA.
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25
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Surface decoration with leucine tetrapeptide: An antibacterial strategy against Gram-negative bacteria. J Colloid Interface Sci 2023; 641:126-134. [PMID: 36931211 DOI: 10.1016/j.jcis.2023.03.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 02/19/2023] [Accepted: 03/05/2023] [Indexed: 03/11/2023]
Abstract
Surface-associated microbe contamination by Gram-negative bacteria poses a serious problem in medical care. Cationic peptides or polymers are the main materials used for antibacterial surface coating, but the positive charge may lead to blood coagulation. Therefore, exploiting surface coating which is free of positive charge and is effective for Gram-negative bacteria inactivation is in urgent need. In this study, inspired by the affinity between lipopolysaccharides of Gram-negative bacteria and Toll-like receptors of immune cells, we develop a leucine-based tetrapeptide coating strategy for combating Gram-negative bacteria. The obtained surface has excellent bactericidal activity against Gram-negative bacteria like Pseudomonas aeruginosa and Escherichia coli. A 1 mm2 coated glass surface could kill > 9.9 × 104 CFU bacteria in 1 h and has nearly no damage to mammal cells. Moreover, this surface coating strategy could be applied on various surfaces like glass slices, glass capillary cavity and thermoplastic polyurethane slices. And the coated surface could largely mitigate the microbe contamination in an in vivo subcutaneous implantation. This work paves a new way for antibacterial surface-coating which is behaving no positive charge and is of great importance for biomedical devices.
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26
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The inhibition mechanism and death mode of Microcystis aeruginosa induced by the continuous pressure of artemisinin sustained-release microspheres (ASMs). ALGAL RES 2023. [DOI: 10.1016/j.algal.2023.103031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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27
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Berne C, Zappa S, Brun YV. eDNA-stimulated cell dispersion from Caulobacter crescentus biofilms upon oxygen limitation is dependent on a toxin-antitoxin system. eLife 2023; 12:e80808. [PMID: 36475544 PMCID: PMC9851616 DOI: 10.7554/elife.80808] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
In their natural environment, most bacteria preferentially live as complex surface-attached multicellular colonies called biofilms. Biofilms begin with a few cells adhering to a surface, where they multiply to form a mature colony. When conditions deteriorate, cells can leave the biofilm. This dispersion is thought to be an important process that modifies the overall biofilm architecture and that promotes colonization of new environments. In Caulobacter crescentus biofilms, extracellular DNA (eDNA) is released upon cell death and prevents newborn cells from joining the established biofilm. Thus, eDNA promotes the dispersal of newborn cells and the subsequent colonization of new environments. These observations suggest that eDNA is a cue for sensing detrimental environmental conditions in the biofilm. Here, we show that the toxin-antitoxin system (TAS) ParDE4 stimulates cell death in areas of a biofilm with decreased O2 availability. In conditions where O2 availability is low, eDNA concentration is correlated with cell death. Cell dispersal away from biofilms is decreased when parDE4 is deleted, probably due to the lower local eDNA concentration. Expression of parDE4 is positively regulated by O2 and the expression of this operon is decreased in biofilms where O2 availability is low. Thus, a programmed cell death mechanism using an O2-regulated TAS stimulates dispersal away from areas of a biofilm with decreased O2 availability and favors colonization of a new, more hospitable environment.
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Affiliation(s)
- Cecile Berne
- Département de microbiologie, infectiologie et immunologie, Université de MontréalMontréalCanada
| | - Sébastien Zappa
- Département de microbiologie, infectiologie et immunologie, Université de MontréalMontréalCanada
| | - Yves V Brun
- Département de microbiologie, infectiologie et immunologie, Université de MontréalMontréalCanada
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28
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Peng Q, Tang X, Dong W, Sun N, Yuan W. A Review of Biofilm Formation of Staphylococcus aureus and Its Regulation Mechanism. Antibiotics (Basel) 2022; 12:antibiotics12010012. [PMID: 36671212 PMCID: PMC9854888 DOI: 10.3390/antibiotics12010012] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/24/2022] Open
Abstract
Bacteria can form biofilms in natural and clinical environments on both biotic and abiotic surfaces. The bacterial aggregates embedded in biofilms are formed by their own produced extracellular matrix. Staphylococcus aureus (S. aureus) is one of the most common pathogens of biofilm infections. The formation of biofilm can protect bacteria from being attacked by the host immune system and antibiotics and thus bacteria can be persistent against external challenges. Therefore, clinical treatments for biofilm infections are currently encountering difficulty. To address this critical challenge, a new and effective treatment method needs to be developed. A comprehensive understanding of bacterial biofilm formation and regulation mechanisms may provide meaningful insights against antibiotic resistance due to bacterial biofilms. In this review, we discuss an overview of S. aureus biofilms including the formation process, structural and functional properties of biofilm matrix, and the mechanism regulating biofilm formation.
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Affiliation(s)
- Qi Peng
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
| | - Xiaohua Tang
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
| | - Wanyang Dong
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
| | - Ning Sun
- Guangzhou First People’s Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
- Correspondence: (N.S.); (W.Y.)
| | - Wenchang Yuan
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou 510180, China
- Correspondence: (N.S.); (W.Y.)
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29
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Franco D, Calabrese G, Guglielmino SPP, Conoci S. Metal-Based Nanoparticles: Antibacterial Mechanisms and Biomedical Application. Microorganisms 2022; 10:microorganisms10091778. [PMID: 36144380 PMCID: PMC9503339 DOI: 10.3390/microorganisms10091778] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/21/2022] [Accepted: 08/31/2022] [Indexed: 11/22/2022] Open
Abstract
The growing increase in antibiotic-resistant bacteria has led to the search for new antibacterial agents capable of overcoming the resistance problem. In recent years, nanoparticles (NPs) have been increasingly used to target bacteria as an alternative to antibiotics. The most promising nanomaterials for biomedical applications are metal and metal oxide NPs, due to their intrinsic antibacterial activity. Although NPs show interesting antibacterial properties, the mechanisms underlying their action are still poorly understood, limiting their use in clinical applications. In this review, an overview of the mechanisms underlying the antibacterial activity of metal and metal oxide NPs will be provided, relating their efficacy to: (i) bacterial strain; (ii) higher microbial organizations (biofilm); (iii) and physico-chemical properties of NPs. In addition, bacterial resistance strategies will be also discussed to better evaluate the feasibility of the different treatments adopted in the clinical safety fields. Finally, a wide analysis on recent biomedical applications of metal and metal oxide NPs with antibacterial activity will be provided.
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Affiliation(s)
- Domenico Franco
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d’Alcontres, 31, 98168 Messina, Italy
| | - Giovanna Calabrese
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d’Alcontres, 31, 98168 Messina, Italy
- Correspondence:
| | - Salvatore Pietro Paolo Guglielmino
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d’Alcontres, 31, 98168 Messina, Italy
| | - Sabrina Conoci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d’Alcontres, 31, 98168 Messina, Italy
- Department of Chemistry ‘‘Giacomo Ciamician’’, University of Bologna, Via Selmi 2, 40126 Bologna, Italy
- LabSense Beyond Nano, URT Department of Physic, National Research Council (CNR), Viale Ferdinando Stagno d’Alcontres, 31, 98168 Messina, Italy
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30
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Molinero N, Conti E, Walker AW, Margolles A, Duncan SH, Delgado S. Survival Strategies and Metabolic Interactions between Ruminococcus gauvreauii and Ruminococcoides bili, Isolated from Human Bile. Microbiol Spectr 2022; 10:e0277621. [PMID: 35863028 PMCID: PMC9431564 DOI: 10.1128/spectrum.02776-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 06/05/2022] [Indexed: 11/26/2022] Open
Abstract
Little is known about the bacteria that reside in the human gallbladder and the mechanisms that allow them to survive within this harsh environment. Here we describe interactions between two strains from a human bile sample, one Ruminococcus gauvreauii (IPLA60001), belonging to the Lachnospiraceae family, and the other, designated as Ruminococcoides bili (IPLA60002T; DSM 110008) most closely related to Ruminococcus bromii within the family Ruminococcaceae. We provide evidence for bile salt resistance and sporulation for these new strains. Both differed markedly in their carbohydrate metabolism. The R. bili strain mainly metabolized resistant starches to form formate, lactate and acetate. R. gauvreauii mainly metabolized sugar alcohols, including inositol and also utilized formate to generate acetate employing the Wood Ljungdahl pathway. Amino acid and vitamin biosynthesis genomic profiles also differed markedly between the two isolates, likely contributing to their synergistic interactions, as revealed by transcriptomic analysis of cocultures. Transcriptome analysis also revealed that R. gauvreauii IPLA60001 is able to grow using the end-products of starch metabolism formed by the R. bili strain such as formate, and potentially other compounds (such as ethanolamine and inositol) possibly provided by the autolytic behavior of R. bili. IMPORTANCE Unique insights into metabolic interaction between two isolates; Ruminococcus gauvreauii IPLA60001 and Ruminococcoides bili IPLA60002, from the human gallbladder, are presented here. The R. bili strain metabolized resistant starches while R. gauvreauii failed to do so but grew well on sugar alcohols. Transcriptomic analysis of cocultures of these strains, provides new data on the physiology and ecology of two bacteria from human bile, with a particular focus on cross-feeding mechanisms. Both biliary strains displayed marked resistance to bile and possess many efflux transporters, potentially involved in bile export. However, they differ markedly in their amino acid catabolism and vitamin synthesis capabilities, a feature that is therefore likely to contribute to the strong synergistic interactions between these strains. This is therefore the first study that provides evidence for syntrophic metabolic cooperation between bacterial strains isolated from human bile.
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Affiliation(s)
- Natalia Molinero
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias (IPLA)-Spanish National Research Council (CSIC), Villaviciosa-Asturias, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo-Asturias, Spain
| | - Elena Conti
- Gut Health Group, Rowett Institute, University of Aberdeen, Foresterhill, Aberdeen, Scotland
| | - Alan W. Walker
- Gut Health Group, Rowett Institute, University of Aberdeen, Foresterhill, Aberdeen, Scotland
| | - Abelardo Margolles
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias (IPLA)-Spanish National Research Council (CSIC), Villaviciosa-Asturias, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo-Asturias, Spain
| | - Sylvia H. Duncan
- Gut Health Group, Rowett Institute, University of Aberdeen, Foresterhill, Aberdeen, Scotland
| | - Susana Delgado
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias (IPLA)-Spanish National Research Council (CSIC), Villaviciosa-Asturias, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo-Asturias, Spain
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31
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Effect of a Stannous Fluoride Dentifrice on Biofilm Composition, Gene Expression and Biomechanical Properties. Microorganisms 2022; 10:microorganisms10091691. [PMID: 36144293 PMCID: PMC9506307 DOI: 10.3390/microorganisms10091691] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
An in situ study was conducted to examine the mode of action of a 0.454% stannous fluoride (SnF2)-containing dentifrice in controlling the composition and properties of oral biofilm. Thirteen generally healthy individuals participated in the study. Each participant wore an intra-oral appliance over a 48-h period to measure differences in the resulting biofilm’s architecture, mechanical properties, and bacterial composition after using two different toothpaste products. In addition, metatranscriptomics analysis of supragingival plaque was conducted to identify the gene pathways influenced. The thickness and volume of the microcolonies formed when brushing with the SnF2 dentifrice were dramatically reduced compared to the control 0.76% sodium monofluorophosphate (MFP)-containing toothpaste. Similarly, the biophysical and nanomechanical properties measured by atomic force microscopy (AFM) demonstrated a significant reduction in biofilm adhesive properties. Metatranscriptomic analysis identified pathways associated with biofilm formation, cell adhesion, quorum sensing, and N-glycosylation that are significantly downregulated with SnF2. This study provides a clinically relevant snapshot of how the use of a stabilized, SnF2 toothpaste formulation can change the spatial organization, nanomechanical, and gene expression properties of bacterial communities.
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Jiang G, Ma J, Wang C, Wang Y, Laghari AA. Kinetics and mechanism analysis on self-decay of airborne bacteria:biological and physical decay under different temperature. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 832:155033. [PMID: 35390386 DOI: 10.1016/j.scitotenv.2022.155033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 03/24/2022] [Accepted: 03/31/2022] [Indexed: 05/13/2023]
Abstract
Bioaerosol as an important medium has aroused widespread concern on its potential hazards in disease transmission and environment biosafety. However, little is known about the duration and self-decay of airborne bacteria in the atmosphere environment. Further, the self-decay process is proposed to include biological-decay and physical-decay. At present, there are many reports on the bacteria apoptosis mechanism and airborne particle migration. However, few studies focus on self-decay during the physical movement of airborne bacteria. The present study investigated self-decay laws and efficiencies of airborne bacteria in the sealed reactor under room temperature (18 ± 2 °C, RT) and low temperature (3 ± 2 °C, LT). The self-decay rate constants of 0.0089, 0.0133, 0.0092, and 0.0122 min-1 were obtained under RT-E. coli, LT-E. coli, RT-S. aureus and LT-S. aureus, respectively. There was no significant difference between the self-decay efficiency of gram-negative and gram-positive bacteria under the same conditions. Nevertheless, gram-negative bacteria were more sensitive to temperature change compared with gram-positive bacteria, where the self-decay efficiency of gram-negative under LT was 49% higher than that under RT, and the value of gram-positive was 32% at the same condition. Furthermore, the laws of biological-decay and physical-decay conformed to the first-order kinetic model by theoretical derivation. Biological-decay accounted for 59.5% at RT and 88.5% at LT among self-decay, which is mainly caused by energy absorption, environmental stress, and bacterial structure changes. Physical-decay mainly caused by gravity settlement accounting for 40% at RT and 10% at LT among self-decay, approximately. Meanwhile, the influence of environmental factors on self-decay was mainly reflected in the biological-decay process. Overall, it is of great significance for clarifying the changing laws of bioaerosol and controlling the transmission of airborne bacteria.
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Affiliation(s)
- Guanyu Jiang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China; Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin 300350, PR China
| | - Jinbiao Ma
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China; Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin 300350, PR China
| | - Can Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China; Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin 300350, PR China.
| | - Yongchao Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China; Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin 300350, PR China
| | - Azhar Ali Laghari
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China; Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin 300350, PR China
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Duarte H, Gummel J, Robles E, Berti D, Fratini E. Ultra-/Small Angle X-ray Scattering (USAXS/SAXS) and Static Light Scattering (SLS) Modeling as a Tool to Determine Structural Changes and Effect on Growth in S. epidermidis. ACS APPLIED BIO MATERIALS 2022; 5:3703-3712. [PMID: 35905477 PMCID: PMC9940853 DOI: 10.1021/acsabm.2c00218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Usually, to characterize bacterial cells' susceptibility to antimicrobials, basic microbiology techniques such as serial dilutions or disk assays are used. In this work, we present an approach focused on combining static light scattering (SLS) and ultra-/small angle X-ray scattering (USAXS/SAXS). This approach was used to support microbiology techniques, with the aim of understanding the structural changes caused to bacteria when they are exposed to different stresses like pH, oxidation, and surfactants. Using USAXS/SAXS and SLS data, we developed a detailed multiscale model for a Gram-positive bacterium, S. epidermidis, and we extracted information regarding changes in the overall size and cell thickness induced by different stresses (i.e., pH and hydrogen peroxide). Increasing the concentration of hydrogen peroxide leads to a progressive reduction in cell wall thickness. Moreover, the concomitant use of pH and hydrogen peroxide provides evidence for a synergy in inhibiting the S. epidermidis growth. These promising results will be used as a starting base to further investigate more complex formulations and improve/refine the data modeling of bacteria in the small angle scattering regime.
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Affiliation(s)
- Hugo Duarte
- Department
of Chemistry “Ugo Schiff” and CSGI, University of Florence, Sesto
Fiorentino, Florence I-50019, Italy,
| | - Jeremie Gummel
- Brussels
Innovation Centre, Temselaan
100, Strombeek-bever B-1853, Belgium
| | - Eric Robles
- Household
Care Analytical, Procter & Gamble Newcastle
Innovation Centre, Newcastle NE12 9TS, United Kingdom
| | - Debora Berti
- Department
of Chemistry “Ugo Schiff” and CSGI, University of Florence, Sesto
Fiorentino, Florence I-50019, Italy
| | - Emiliano Fratini
- Department
of Chemistry “Ugo Schiff” and CSGI, University of Florence, Sesto
Fiorentino, Florence I-50019, Italy,
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Sionov RV, Banerjee S, Bogomolov S, Smoum R, Mechoulam R, Steinberg D. Targeting the Achilles' Heel of Multidrug-Resistant Staphylococcus aureus by the Endocannabinoid Anandamide. Int J Mol Sci 2022; 23:7798. [PMID: 35887146 PMCID: PMC9319909 DOI: 10.3390/ijms23147798] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/10/2022] [Accepted: 07/12/2022] [Indexed: 02/06/2023] Open
Abstract
Antibiotic-resistant Staphylococcus aureus is a major health issue that requires new therapeutic approaches. Accumulating data suggest that it is possible to sensitize these bacteria to antibiotics by combining them with inhibitors targeting efflux pumps, the low-affinity penicillin-binding protein PBP2a, cell wall teichoic acid, or the cell division protein FtsZ. We have previously shown that the endocannabinoid Anandamide (N-arachidonoylethanolamine; AEA) could sensitize drug-resistant S. aureus to a variety of antibiotics, among others, through growth arrest and inhibition of drug efflux. Here, we looked at biochemical alterations caused by AEA. We observed that AEA increased the intracellular drug concentration of a fluorescent penicillin and augmented its binding to membrane proteins with concomitant altered membrane distribution of these proteins. AEA also prevented the secretion of exopolysaccharides (EPS) and reduced the cell wall teichoic acid content, both processes known to require transporter proteins. Notably, AEA was found to inhibit membrane ATPase activity that is necessary for transmembrane transport. AEA did not affect the membrane GTPase activity, and the GTPase cell division protein FtsZ formed the Z-ring of the divisome normally in the presence of AEA. Rather, AEA caused a reduction in murein hydrolase activities involved in daughter cell separation. Altogether, this study shows that AEA affects several biochemical processes that culminate in the sensitization of the drug-resistant bacteria to antibiotics.
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Affiliation(s)
- Ronit Vogt Sionov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Shreya Banerjee
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Sergei Bogomolov
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
| | - Reem Smoum
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Raphael Mechoulam
- Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (R.S.); (R.M.)
| | - Doron Steinberg
- Biofilm Research Laboratory, Institute of Biomedical and Oral Sciences, Faculty of Dentistry, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (S.B.); (S.B.); (D.S.)
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Abstract
Gene expression divergence through evolutionary processes is thought to be important for achieving programmed development in multicellular organisms. To test this premise in filamentous fungi, we investigated transcriptional profiles of 3,942 single-copy orthologous genes (SCOGs) in five related sordariomycete species that have morphologically diverged in the formation of their flask-shaped perithecia. We compared expression of the SCOGs to inferred gene expression levels of the most recent common ancestor of the five species, ranking genes from their largest increases to smallest increases in expression during perithecial development in each of the five species. We found that a large proportion of the genes that exhibited evolved increases in gene expression were important for normal perithecial development in Fusarium graminearum. Many of these genes were previously uncharacterized, encoding hypothetical proteins without any known functional protein domains. Interestingly, the developmental stages during which aberrant knockout phenotypes appeared largely coincided with the elevated expression of the deleted genes. In addition, we identified novel genes that affected normal perithecial development in Magnaporthe oryzae and Neurospora crassa, which were functionally and transcriptionally diverged from the orthologous counterparts in F. graminearum. Furthermore, comparative analysis of developmental transcriptomes and phylostratigraphic analysis suggested that genes encoding hypothetical proteins are generally young and transcriptionally divergent between related species. This study provides tangible evidence of shifts in gene expression that led to acquisition of novel function of orthologous genes in each lineage and demonstrates that several genes with hypothetical function are crucial for shaping multicellular fruiting bodies. IMPORTANCE The fungal class Sordariomycetes includes numerous important plant and animal pathogens. It also provides model systems for studying fungal fruiting body development, as its members develop fruiting bodies with a few well-characterized tissue types on common growth media and have rich genomic resources that enable comparative and functional analyses. To understand transcriptional divergence of key developmental genes between five related sordariomycete fungi, we performed targeted knockouts of genes inferred to have evolved significant upward shifts in expression. We found that many previously uncharacterized genes play indispensable roles at different stages of fruiting body development, which have undergone transcriptional activation in specific lineages. These novel genes are predicted to be phylogenetically young and tend to be involved in lineage- or species-specific function. Transcriptional activation of genes with unknown function seems to be more frequent than ever thought, which may be crucial for rapid adaption to changing environments for successful sexual reproduction.
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Wang M, Buist G, van Dijl JM. Staphylococcus aureus cell wall maintenance - the multifaceted roles of peptidoglycan hydrolases in bacterial growth, fitness, and virulence. FEMS Microbiol Rev 2022; 46:6604383. [PMID: 35675307 PMCID: PMC9616470 DOI: 10.1093/femsre/fuac025] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/22/2022] [Accepted: 05/25/2022] [Indexed: 01/07/2023] Open
Abstract
Staphylococcus aureus is an important human and livestock pathogen that is well-protected against environmental insults by a thick cell wall. Accordingly, the wall is a major target of present-day antimicrobial therapy. Unfortunately, S. aureus has mastered the art of antimicrobial resistance, as underscored by the global spread of methicillin-resistant S. aureus (MRSA). The major cell wall component is peptidoglycan. Importantly, the peptidoglycan network is not only vital for cell wall function, but it also represents a bacterial Achilles' heel. In particular, this network is continuously opened by no less than 18 different peptidoglycan hydrolases (PGHs) encoded by the S. aureus core genome, which facilitate bacterial growth and division. This focuses attention on the specific functions executed by these enzymes, their subcellular localization, their control at the transcriptional and post-transcriptional levels, their contributions to staphylococcal virulence and their overall importance in bacterial homeostasis. As highlighted in the present review, our understanding of the different aspects of PGH function in S. aureus has been substantially increased over recent years. This is important because it opens up new possibilities to exploit PGHs as innovative targets for next-generation antimicrobials, passive or active immunization strategies, or even to engineer them into effective antimicrobial agents.
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Affiliation(s)
- Min Wang
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | | | - Jan Maarten van Dijl
- Corresponding author: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, HPC EB80, 9700 RB Groningen, the Netherlands, Tel. +31-50-3615187; Fax. +31-50-3619105; E-mail:
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G C B, Sahukhal GS, Elasri MO. Delineating the Role of the msaABCR Operon in Staphylococcal Overflow Metabolism. Front Microbiol 2022; 13:914512. [PMID: 35722290 PMCID: PMC9204165 DOI: 10.3389/fmicb.2022.914512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 05/12/2022] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus is an important human pathogen that can infect almost every organ system, resulting in a high incidence of morbidity and mortality. The msaABCR operon is an important regulator of several staphylococcal phenotypes, including biofilm development, cell wall crosslinking, antibiotic resistance, oxidative stress, and acute and chronic implant-associated osteomyelitis. Our previous study showed that, by modulating murein hydrolase activity, the msaABCR operon negatively regulates the proteases that govern cell death. Here, we report further elucidation of the mechanism of cell death, which is regulated by the msaABCR operon at the molecular level in the USA300 LAC strain. We showed that deletion of msaABCR enhances weak-acid-dependent cell death, because, in the biofilm microenvironment, this mutant strain consumes glucose and produces acetate and acetoin at higher rates than wild-type USA300 LAC strain. We proposed the increased intracellular acidification leads to increased cell death. MsaB, a dual-function transcription factor and RNA chaperone, is a negative regulator of the cidR regulon, which has been shown to play an important role in overflow metabolism and programmed cell death during biofilm development in S. aureus. We found that MsaB binds directly to the cidR promoter, which represses expression of the cidR regulon and prevents transcription of the cidABC and alsSD operons. In addition, we observed that pyruvate induced expression of the msaABCR operon (MsaB). The results reported here have enabled us to decipher the role of the msaABCR operon in staphylococcal metabolic adaption during biofilm development.
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Affiliation(s)
- Bibek G C
- Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Gyan S. Sahukhal
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
- *Correspondence: Gyan S. Sahukhal,
| | - Mohamed O. Elasri
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
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Calcuttawala F, Shaw R, Sarbajna A, Dutta M, Sinha S, K. Das Gupta S. Apoptosis like symptoms associated with abortive infection of Mycobacterium smegmatis by mycobacteriophage D29. PLoS One 2022; 17:e0259480. [PMID: 35580120 PMCID: PMC9113562 DOI: 10.1371/journal.pone.0259480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 04/29/2022] [Indexed: 01/12/2023] Open
Abstract
Mycobacteriophages are phages that infect mycobacteria resulting in their killing. Although lysis is the primary mechanism by which mycobacteriophages cause cell death, others such as abortive infection may also be involved. We took recourse to perform immunofluorescence and electron microscopic studies using mycobacteriophage D29 infected Mycobacterium smegmatis cells to investigate this issue. We could observe the intricate details of the infection process using these techniques such as adsorption, the phage tail penetrating the thick mycolic acid layer, formation of membrane pores, membrane blebbing, and phage release. We observed a significant increase in DNA fragmentation and membrane depolarization using cell-biological techniques symptomatic of programmed cell death (PCD). As Toxin-Antitoxin (TA) systems mediate bacterial PCD, we measured their expression profiles with and without phage infection. Of the three TAs examined, MazEF, VapBC, and phd/doc, we found that in the case of VapBC, a significant decrease in the antitoxin (VapB): toxin (VapC) ratio was observed following phage infection, implying that high VapC may have a role to play in the induction of mycobacterial apoptotic cell death following phage infection. This study indicates that D29 infection causes mycobacteria to undergo morphological and molecular changes that are hallmarks of apoptotic cell death.
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Affiliation(s)
- Fatema Calcuttawala
- Department of Microbiology, Sister Nivedita University, Kolkata, India
- * E-mail:
| | - Rahul Shaw
- Department of Microbiology, Bose Institute, Kolkata, India
| | - Arpita Sarbajna
- Division of Electron Microscopy, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Moumita Dutta
- Division of Electron Microscopy, National Institute of Cholera and Enteric Diseases, Kolkata, India
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The WalRK Two-Component System Is Essential for Proper Cell Envelope Biogenesis in Clostridioides difficile. J Bacteriol 2022; 204:e0012122. [PMID: 35575581 PMCID: PMC9210968 DOI: 10.1128/jb.00121-22] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The WalR-WalK two-component regulatory system (TCS) is found in all Firmicutes, in which it regulates the expression of multiple genes required for remodeling the cell envelope during growth and division. Unlike most TCSs, WalRK is essential for viability, so it has attracted interest as a potential antibiotic target. In this study, we used overexpression of WalR and CRISPR interference to investigate the Wal system of Clostridioides difficile, a major cause of hospital-associated diarrhea in high-income countries. We confirmed that the wal operon is essential and identified morphological defects and cell lysis as the major terminal phenotypes of altered wal expression. We also used transcriptome sequencing (RNA-seq) to identify over 150 genes whose expression changes in response to WalR levels. This gene set is enriched in cell envelope genes and includes genes encoding several predicted PG hydrolases and proteins that could regulate PG hydrolase activity. A distinct feature of the C. difficile cell envelope is the presence of an S-layer, and we found that WalR affects expression of several genes which encode S-layer proteins. An unexpected finding was that some Wal-associated phenotypic defects were inverted in comparison to what has been reported for other Firmicutes. For example, downregulation of Wal signaling caused C. difficile cells to become longer rather than shorter, as in Bacillus subtilis. Likewise, downregulation of Wal rendered C. difficile more sensitive to vancomycin, whereas reduced Wal activity is linked to increased vancomycin resistance in Staphylococcus aureus. IMPORTANCE The WalRK two-component system (TCS) is essential for coordinating synthesis and turnover of peptidoglycan in Firmicutes. We investigated the WalRK TCS in Clostridioides difficile, an important bacterial pathogen with an atypical cell envelope. We confirmed that WalRK is essential and regulates cell envelope biogenesis, although several of the phenotypic changes we observed were opposite to what has been reported for other Firmicutes. We also identified over 150 genes whose expression is controlled either directly or indirectly by WalR. Overall, our findings provide a foundation for future investigations of an important regulatory system and potential antibiotic target in C. difficile.
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Zank A, Schulte L, Brandon X, Carstensen L, Wescott A, Schwan WR. Mutations of the brpR and brpS genes affect biofilm formation in Staphylococcus aureus. World J Clin Infect Dis 2022; 12:20-32. [DOI: 10.5495/wjcid.v12.i1.20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 12/03/2021] [Accepted: 02/13/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND In the United States, Staphylococcus aureus (S. aureus) kills tens of thousands of individuals each year and the formation of a biofilm contributes to lethality. Biofilm-associated infections are hard to treat once the biofilm has formed. A new stilbene drug, labeled SK-03-92, was shown to kill S. aureus and affected transcription of two genes tied to a putative two-component system (TCS) we have named brpR (biofilm regulating protein regulator) and brpS (biofilm regulating protein sensor).
AIM To determine if BrpR and BrpS regulate biofilm formation, brpR and brpS mutants were assessed using biofilm assays compared to wild-type S. aureus.
METHODS A combination of biofilm and quantitative real-time-polymerase chain reaction assays were used. In addition, bioinformatic software tools were also utilized.
RESULTS Significantly more biofilm was created in the brpR and brpS mutants vs wild-type cells. Quantitative real-time polymerase chain reactions showed the brpS mutant had differences in transcription of biofilm associated genes that were eight-fold higher for srtA, two-fold lower for lrgA, and 1.6-fold higher for cidA compared to wild-type. Bioinformatic analysis demonstrated that the S. aureus brpR/brpS TCS had homology to streptococcal late-stage competence proteins involved in cell-death, increased biofilm production, and the development of persister cells.
CONCLUSION Our study suggests that brpR/brpS is a TCS that may repress S. aureus biofilm production and be linked to late-stage competence in S. aureus.
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Affiliation(s)
- Allison Zank
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, United States
| | - Lillian Schulte
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, United States
| | - Xavier Brandon
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, United States
| | - Lauren Carstensen
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, United States
| | - Amy Wescott
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, United States
| | - William R Schwan
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, United States
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Naseri M, Maliha M, Dehghani M, Simon GP, Batchelor W. Rapid Detection of Gram-Positive and -Negative Bacteria in Water Samples Using Mannan-Binding Lectin-Based Visual Biosensor. ACS Sens 2022; 7:951-959. [PMID: 35290028 DOI: 10.1021/acssensors.1c01748] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Waterborne bacterial infection is a health threat worldwide, making accurate and timely bacteria detection crucial to prevent waterborne disease outbreaks. Inspired by the intrinsic capability of mannan-binding lectin (MBL) in recognizing the pathogen-associated molecular patterns (PAMPs), a visual biosensor is developed here for the on-site detection of both Gram-positive and -negative bacteria. The biosensor was synthesized by immobilization of the MBL protein onto the blue carboxyl-functionalized polystyrene microparticles (PSM), which is then used in a two-step assay to detect bacterial cells in water samples. The first step involved a 20 min incubation following the MBL-PSM and calcium chloride solution addition to the samples. The second step was to add ethanol to the resultant blue mixture and observe the color change with the naked eye after 15 min. The biosensor had a binary (all-or-none) response, which in the presence of bacterial cells kept its blue color, while in their absence the color changed from blue to colorless. Testing the water samples spiked with four Gram-negative bacteria including Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa and two Gram-positive bacteria of Enterococcus faecalis and Staphylococcus aureus showed that the biosensor could detect all tested bacteria with a concentration as low as 101.5 CFU/ml. The performance of biosensor using the water samples from a water treatment plant also confirmed its capability to detect the pathogens in real-life water samples without the need for instrumentation.
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Affiliation(s)
- Mahdi Naseri
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Maisha Maliha
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Mostafa Dehghani
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - George P Simon
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Warren Batchelor
- Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
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Proctor C, Garner E, Hamilton KA, Ashbolt NJ, Caverly LJ, Falkinham JO, Haas CN, Prevost M, Prevots DR, Pruden A, Raskin L, Stout J, Haig SJ. Tenets of a holistic approach to drinking water-associated pathogen research, management, and communication. WATER RESEARCH 2022; 211:117997. [PMID: 34999316 PMCID: PMC8821414 DOI: 10.1016/j.watres.2021.117997] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 12/13/2021] [Accepted: 12/19/2021] [Indexed: 05/10/2023]
Abstract
In recent years, drinking water-associated pathogens that can cause infections in immunocompromised or otherwise susceptible individuals (henceforth referred to as DWPI), sometimes referred to as opportunistic pathogens or opportunistic premise plumbing pathogens, have received considerable attention. DWPI research has largely been conducted by experts focusing on specific microorganisms or within silos of expertise. The resulting mitigation approaches optimized for a single microorganism may have unintended consequences and trade-offs for other DWPI or other interests (e.g., energy costs and conservation). For example, the ecological and epidemiological issues characteristic of Legionella pneumophila diverge from those relevant for Mycobacterium avium and other nontuberculous mycobacteria. Recent advances in understanding DWPI as part of a complex microbial ecosystem inhabiting drinking water systems continues to reveal additional challenges: namely, how can all microorganisms of concern be managed simultaneously? In order to protect public health, we must take a more holistic approach in all aspects of the field, including basic research, monitoring methods, risk-based mitigation techniques, and policy. A holistic approach will (i) target multiple microorganisms simultaneously, (ii) involve experts across several disciplines, and (iii) communicate results across disciplines and more broadly, proactively addressing source water-to-customer system management.
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Affiliation(s)
- Caitlin Proctor
- Department of Agricultural and Biological Engineering, Division of Environmental and Ecological Engineering, Purdue University, West Lafayette, IN, USA
| | - Emily Garner
- Wadsworth Department of Civil & Environmental Engineering, West Virginia University, Morgantown, WV, USA
| | - Kerry A Hamilton
- School of Sustainable Engineering and the Built Environment and The Biodesign Centre for Environmental Health Engineering, Arizona State University, Tempe, AZ, USA
| | - Nicholas J Ashbolt
- Faculty of Science and Engineering, Southern Cross University, Gold Coast. Queensland, Australia
| | - Lindsay J Caverly
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Charles N Haas
- Department of Civil, Architectural & Environmental Engineering, Drexel University, Philadelphia, PA, USA
| | - Michele Prevost
- Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, Canada
| | - D Rebecca Prevots
- Epidemiology Unit, Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Amy Pruden
- Department of Civil & Environmental Engineering, Virginia Tech, Blacksburg, VA USA
| | - Lutgarde Raskin
- Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Janet Stout
- Department of Civil & Environmental Engineering, University of Pittsburgh, and Special Pathogens Laboratory, Pittsburgh, PA, USA
| | - Sarah-Jane Haig
- Department of Civil & Environmental Engineering, and Department of Environmental & Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA.
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Organomercurial lyase (MerB)-mediated demethylation decreases bacterial methylmercury resistance in the absence of mercuric reductase (MerA). Appl Environ Microbiol 2022; 88:e0001022. [PMID: 35138926 DOI: 10.1128/aem.00010-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mer operon encodes enzymes that transform and detoxify methylmercury (MeHg) and/or inorganic mercury (Hg(II)). Organomercurial lyase (MerB) and mercuric reductase (MerA) can act sequentially to demethylate MeHg to Hg(II) and reduce Hg(II) to volatile elemental mercury (Hg0) that can escape from the cell, conferring resistance to MeHg and Hg(II). Most identified mer operons encode either MerA and MerB in tandem or MerA alone, however, microbial genomes were recently identified that encode only MerB. Yet, the effects of potentially producing intracellular Hg(II) via demethylation of MeHg by MerB, independent of a mechanism to further detoxify or sequester the metal is not well understood. Here, we investigate MeHg biotransformation in Escherichia coli strains engineered to express MerA and MerB, together or separately, and characterize cell viability and Hg detoxification kinetics when these strains are grown in the presence of MeHg. Strains expressing only MerB are capable of demethylating MeHg to Hg(II). Compared to strains that express both MerA and MerB, strains expressing only MerB exhibit a lower minimum inhibitory concentration with MeHg exposure, which parallels a redistribution of Hg from the cell-associated fraction to the culture medium, consistent with cell lysis occurring. The data support a model whereby intracellular production of Hg(II), in the absence of reduction or other forms of demobilization, results in a greater cytotoxicity compared to the parent MeHg compound. Collectively, these results suggest that in the context of MeHg detoxification, MerB must be accompanied by an additional mechanism(s) to reduce, sequester, or re-distribute generated Hg(II). Importance: Mercury is a globally distributed pollutant that poses a risk to wildlife and human health. The toxicity of mercury is influenced largely by microbially mediated biotransformation between its organic (methylmercury) and inorganic (Hg(II) and Hg0) forms. Here we show in a relevant cellular context that the organomercurial lyase (MerB) enzyme is capable of MeHg demethylation without subsequent mercuric reductase (MerA)-mediated reduction of Hg(II). Demethylation of MeHg without subsequent Hg(II) reduction results in a greater cytotoxicity and increased cell lysis. Microbes carrying MerB alone have recently been identified but have yet to be characterized. Our results demonstrate that mer operons encoding MerB but not MerA put the cell at a disadvantage in the context of MeHg exposure, unless subsequent mechanisms of reduction or Hg(II) sequestration exist. These findings may help uncover the existence of alternative mechanisms of Hg(II) detoxification in addition to revealing the drivers of mer operon evolution.
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Gouveia A, Pinto D, Veiga H, Antunes W, Pinho MG, São-José C. Synthetic antimicrobial peptides as enhancers of the bacteriolytic action of staphylococcal phage endolysins. Sci Rep 2022; 12:1245. [PMID: 35075218 PMCID: PMC8786859 DOI: 10.1038/s41598-022-05361-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 01/10/2022] [Indexed: 01/09/2023] Open
Abstract
Bacteriophage endolysins degrade the bacterial cell wall and are therefore considered promising antimicrobial alternatives to fight pathogens resistant to conventional antibiotics. Gram-positive bacteria are usually considered easy targets to exogenously added endolysins, since their cell walls are not shielded by an outer membrane. However, in nutrient rich environments these bacteria can also tolerate endolysin attack if they keep an energized cytoplasmic membrane. Hence, we have hypothesized that the membrane depolarizing action of antimicrobial peptides (AMPs), another attractive class of alternative antibacterials, could be explored to overcome bacterial tolerance to endolysins and consequently improve their antibacterial potential. Accordingly, we show that under conditions supporting bacterial growth, Staphylococcus aureus becomes much more susceptible to the bacteriolytic action of endolysins if an AMP is also present. The bactericidal gain resulting from the AMP/endolysin combined action ranged from 1 to 3 logs for different S. aureus strains, which included drug-resistant clinical isolates. In presence of an AMP, as with a reduced content of cell wall teichoic acids, higher endolysin binding to cells is observed. However, our results indicate that this higher endolysin binding alone does not fully explain the higher susceptibility of S. aureus to lysis in these conditions. Other factors possibly contributing to the increased endolysin susceptibility in presence of an AMP are discussed.
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Affiliation(s)
- Ana Gouveia
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia da Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisbon, Portugal
| | - Daniela Pinto
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia da Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisbon, Portugal
| | - Helena Veiga
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da Républica, 2780-157, Oeiras, Portugal
| | - Wilson Antunes
- Unidade Militar Laboratorial de Defesa Biológica e Química (UMLDBQ), Instituto Universitário Militar, Centro de Investigação da Academia Militar (CINAMIL), Av. Dr. Alfredo Bensaúde, 1849-012, Lisbon, Portugal
| | - Mariana G Pinho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da Républica, 2780-157, Oeiras, Portugal
| | - Carlos São-José
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia da Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisbon, Portugal.
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Magnesium rescues the morphology of Bacillus subtilis mreB mutants through its inhibitory effect on peptidoglycan hydrolases. Sci Rep 2022; 12:1137. [PMID: 35064120 PMCID: PMC8782873 DOI: 10.1038/s41598-021-04294-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/06/2021] [Indexed: 02/04/2023] Open
Abstract
Cell wall homeostasis in bacteria is tightly regulated by balanced synthesis and degradation of peptidoglycan (PG), allowing cells to expand their sacculus during growth while maintaining physical integrity. In rod-shaped bacteria, actin-like MreB proteins are key players of the PG elongation machinery known as the Rod complex. In the Gram-positive model bacterium Bacillus subtilis depletion of the essential MreB leads to loss of rod shape and cell lysis. However, millimolar concentrations of magnesium in the growth medium rescue the viability and morphological defects of mreB mutants by an unknown mechanism. Here, we used a combination of cytological, biochemical and biophysical approaches to investigate the cell surface properties of mreB null mutant cells and the interactions of Mg2+ with the cell wall of B. subtilis. We show that ∆mreB cells have rougher and softer surfaces, and changes in PG composition indicative of increased DL- and DD-endopeptidase activities as well as increased deacetylation of the sugar moieties. Increase in DL-endopeptidase activity is mitigated by excess Mg2+ while DD-endopeptidase activity remains high. Visualization of PG degradation in pulse-chase experiments showed anisotropic PG hydrolase activity along the sidewalls of ∆mreB cells, in particular at the sites of increased cell width and bulging, while PG synthesis remained isotropic. Overall, our data support a model in which divalent cations maintain rod shape in ∆mreB cells by inhibiting PG hydrolases, possibly through the formation of crosslinks with carboxyl groups of the PG meshwork that affect the capacity of PG hydrolases to act on their substrate.
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Tímermans A, Vázquez R, Otero F, Gosálvez J, Johnston S, Fernández JL. Antibiotic toxicity on human spermatozoa assessed using the sperm DNA fragmentation dynamic assay. Andrologia 2021; 54:e14328. [PMID: 34837416 DOI: 10.1111/and.14328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/18/2021] [Accepted: 11/12/2021] [Indexed: 02/06/2023] Open
Abstract
Sperm DNA fragmentation (SDF) dynamic assays were piloted on 4 fresh ejaculates to examine the possible sperm toxicity of three common antibiotics, ciprofloxacin, doxycycline and ampicillin, incubated at a concentration estimated to be reached in semen in vivo, and 100×, for 24 h. SDF was assessed in terms of single-strand DNA breaks (SSBs) and double-strand DNA breaks (DSBs). Low and high concentrations of ciprofloxacin and high concentration of doxycycline significantly increased the SDF rate, due to sperm containing SSBs. Ampicillin did not affect SDF dynamics at any dose. Based on these results, the effect of antibiotics on the global-SDF dynamics was further examined in 21 ejaculates assessed at 0, 4 and 6 h. Ciprofloxacin increased the rate of SDF at the low concentration in 17 from 21 subjects; the high concentration resulted in a stronger effect in all individuals. A significant increase in the rate of SDF in 17 ejaculates was also noted when spermatozoa were incubated with the high concentration of doxycycline. The dynamic SDF assay is a rapid and sensitive tool to evidence sperm toxicity. Ciprofloxacin should be avoided when it is necessary to preserve sperm quality for reproductive purposes and as additive in semen diluents.
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Affiliation(s)
- Ana Tímermans
- Genetics Unit, INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain.,Laboratory of Molecular Genetics and Radiobiology, Centro Oncológico de Galicia, A Coruña, Spain
| | | | - Fátima Otero
- Genetics Unit, INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain.,Laboratory of Molecular Genetics and Radiobiology, Centro Oncológico de Galicia, A Coruña, Spain
| | - Jaime Gosálvez
- Genetics Unit, Facultad de Biología, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, Madrid, Spain
| | - Stephen Johnston
- School of Agriculture and Food Sciences, The University of Queensland, Gatton, Australia
| | - José Luis Fernández
- Genetics Unit, INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain.,Laboratory of Molecular Genetics and Radiobiology, Centro Oncológico de Galicia, A Coruña, Spain
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Kumar N, Mittal A, Yadav M, Sharma S, Kumar T, Chakraborty R, Sengupta S, Chauhan NS. Photocatalytic TiO 2/CdS/ZnS nanocomposite induces Bacillus subtilis cell death by disrupting its metabolism and membrane integrity. Indian J Microbiol 2021; 61:487-496. [PMID: 34744204 DOI: 10.1007/s12088-021-00973-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 08/08/2021] [Indexed: 12/24/2022] Open
Abstract
Titanium dioxide (TiO2) is widely characterized for its application in clinical diagnostics, therapeutics, cosmetics, nutrition, and environment management. Despite enormous potential, its dependence on ultraviolet (UV) light for photocatalytic activity limits its commercialization. Accordingly in the present study, a photo catalytically superior ternary complex of TiO2 with Cadmium sulfide/Zinc sulfide (CdS/ZnS) has been synthesized, as well as, characterized for photo-induced antimicrobial activity. The band gap of crystalline TiO2/CdS/ZnS nanocomposite has been reduced (2.26 eV) and nanocomposite has shown the optimal photo-activation at 590 nm. TiO2 nanocomposite has significant bactericidal activity in visible light (P < 0.01). Exposure of the TiO2 nanocomposite affected the cellular metabolism by altering the 1681 metabolic features (P < 0.001) culminating in poor cellular survivability. Additionally, photo-induced reactive oxygen species generation through nanocomposite disrupts the microbial cellular structure. The present study synthesized photocatalytic nanocomposite as well as unveiled the holistic cellular effect of theTiO2/CdS/ZnS nanocomposite. Additionally, the present study also indicated the potential application of TiO2/CdS/ZnS nanocomposite for sustainable environment management, therapeutics, and various industries. Supplementary Information The online version contains supplementary material available at 10.1007/s12088-021-00973-z.
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Affiliation(s)
- Naveen Kumar
- Department of Chemistry, Maharshi Dayanand University, Rohtak, Haryana India
| | - Anuj Mittal
- Department of Chemistry, Maharshi Dayanand University, Rohtak, Haryana India
| | - Monika Yadav
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, Haryana India
| | - Shankar Sharma
- Department of Chemistry, Maharshi Dayanand University, Rohtak, Haryana India
| | - Tarun Kumar
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, Haryana India
| | - Rahul Chakraborty
- Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Shantanu Sengupta
- Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Nar Singh Chauhan
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, Haryana India
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Investigating Extracellular DNA Release in Staphylococcus xylosus Biofilm In Vitro. Microorganisms 2021; 9:microorganisms9112192. [PMID: 34835318 PMCID: PMC8617998 DOI: 10.3390/microorganisms9112192] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/08/2021] [Accepted: 10/19/2021] [Indexed: 12/29/2022] Open
Abstract
Staphylococcus xylosus forms biofilm embedded in an extracellular polymeric matrix. As extracellular DNA (eDNA) resulting from cell lysis has been found in several staphylococcal biofilms, we investigated S. xylosus biofilm in vitro by a microscopic approach and identified the mechanisms involved in cell lysis by a transcriptomic approach. Confocal laser scanning microscopy (CLSM) analyses of the biofilms, together with DNA staining and DNase treatment, revealed that eDNA constituted an important component of the matrix. This eDNA resulted from cell lysis by two mechanisms, overexpression of phage-related genes and of cidABC encoding a holin protein that is an effector of murein hydrolase activity. This lysis might furnish nutrients for the remaining cells as highlighted by genes overexpressed in nucleotide salvage, in amino sugar catabolism and in inorganic ion transports. Several genes involved in DNA/RNA repair and genes encoding proteases and chaperones involved in protein turnover were up-regulated. Furthermore, S. xylosus perceived osmotic and oxidative stresses and responded by up-regulating genes involved in osmoprotectant synthesis and in detoxification. This study provides new insight into the physiology of S. xylosus in biofilm.
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C4 Bacterial Volatiles Improve Plant Health. Pathogens 2021; 10:pathogens10060682. [PMID: 34072921 PMCID: PMC8227687 DOI: 10.3390/pathogens10060682] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/10/2021] [Accepted: 05/24/2021] [Indexed: 02/04/2023] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) associated with plant roots can trigger plant growth promotion and induced systemic resistance. Several bacterial determinants including cell-wall components and secreted compounds have been identified to date. Here, we review a group of low-molecular-weight volatile compounds released by PGPR, which improve plant health, mostly by protecting plants against pathogen attack under greenhouse and field conditions. We particularly focus on C4 bacterial volatile compounds (BVCs), such as 2,3-butanediol and acetoin, which have been shown to activate the plant immune response and to promote plant growth at the molecular level as well as in large-scale field applications. We also disc/ uss the potential applications, metabolic engineering, and large-scale fermentation of C4 BVCs. The C4 bacterial volatiles act as airborne signals and therefore represent a new type of biocontrol agent. Further advances in the encapsulation procedure, together with the development of standards and guidelines, will promote the application of C4 volatiles in the field.
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Antibacterial Optimization of Highly Deformed Titanium Alloys for Spinal Implants. Molecules 2021; 26:molecules26113145. [PMID: 34074062 PMCID: PMC8197332 DOI: 10.3390/molecules26113145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 12/31/2022] Open
Abstract
The goal of the work was to develop materials dedicated to spine surgery that minimized the potential for infection originating from the transfer of bacteria during long surgeries. The bacteria form biofilms, causing implant loosening, pain and finally, a risk of paralysis for patients. Our strategy focused both on improvement of antibacterial properties against bacteria adhesion and on wear and corrosion resistance of tools for spine surgery. Further, a ~35% decrease in implant and tool dimensions was expected by introducing ultrahigh-strength titanium alloys for less-invasive surgeries. The tested materials, in the form of thin, multi-layered coatings, showed nanocrystalline microstructures. Performed direct-cytotoxicity studies (including lactate dehydrogenase activity measurement) showed that there was a low probability of adverse effects on surrounding SAOS-2 (Homo sapiens bone osteosarcoma) cells. The microbiological studies (e.g., ISO 22196 contact tests) showed that implanting Ag nanoparticles into Ti/TixN coatings inhibited the growth of E. coli and S. aureus cells and reduced their adhesion to the material surface. These findings suggest that Ag-nanoparticles present in implant coatings may potentially minimize infection risk and lower inherent stress.
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